Doxepin analogs and methods of use thereof

ABSTRACT

The invention relates to novel doxepin analog compounds and methods of modulating sleep by administering such compounds, or a pharmaceutically effective salt thereof.

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. 119(e) to U.S. provisional patent application Ser. No. 60/528,393, filed Dec. 10, 2003, and is a Continuation In Part of U.S. patent application Ser. No. 10/831,423, filed Apr. 23, 2004. The entire contents of each application are incorporated by reference herein.

FIELD OF THE INVENTION

The invention relates to methods for treating sleep disorders and compositions useful in such methods.

BACKGROUND OF THE INVENTION

Difficulty falling asleep or remaining asleep is a significant medical issue that arises for a variety of reasons. Sometimes, these problems arise from endogenous conditions such as sleep apnea or insomnia. Other times, these problems arise from exogenous stresses such as the disruptive effect of shift work schedules and “jet lag.” Whether caused by an endogenous or exogenous source, difficulty falling asleep or remaining asleep can result in problem sleepiness, which impairs the health, quality of life and safety of those affected.

Existing pharmaceutical treatments for inducing sleep include sedatives or hypnotics such as benzodiazepine and barbiturate derivatives. These treatments have numerous drawbacks, including rebound insomnia, delayed onset of desired sedative effects, persistence of sedative effects after the desired sleep period, and side effects due to nonspecific activity such as psychomotor and memory deficits, myorelaxation, and disturbed sleep architecture, including REM sleep inhibition. Additionally, sedatives and hypnotics can be habit forming, can lose their effectiveness after extended use and may be metabolized more slowly by some people.

Consequently, physicians often recommend or prescribe antihistamines as a milder treatment for sleep disorders when hypnotics are less appropriate. However, many antihistamines still have a number of side effects. Other issues include prolongation of the QT interval in a subject's electrocardiogram, as well as central nervous system (CNS) side effects such as decreased muscle tone, drooping eyelids and drowsiness. Finally, such compounds can bind to muscarinic receptors, which leads to anti-cholinergic side effects such as blurred vision, dry mouth, constipation, urinary problems, dizziness and anxiety.

As a result, there is a need for sleep-related treatments with reduced side effects. Additionally, while known sleep-inducing compounds are effective for treating sleep-onset insomnia, i.e., a subject's difficulty in falling asleep, there are no drugs currently indicated for treating sleep maintenance insomnia, i.e., maintaining a subject's sleep throughout a normal sleep period after falling asleep. Therefore, there is also a need for improved pharmaceutical treatments for maintaining sleep in subjects in need of such treatment.

SUMMARY OF THE INVENTION

The present invention relates to doxepin analogs compounds and their use to modulate sleep.

In one aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of a compound having the formula of Formula I:

or a pharmaceutically effective salt thereof, wherein m n, o, p, q are, individually, 0, 1, 2, 3, 4, 5, or 6; X and Y are, individually, absent, O, S, C(O), SO or SO₂; R₁, R₂, R₃, R₄, R₅, R, R₇, and R₈ are, independently selected from the group consisting of H, F, Cl, Br, I, CF₃, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, C₃–C₇ cycloalkyl, C₃–C₇ heterocyclyl, OCH₃, OCF₃, CH₂OCH₃, CH₂CH₂OCH₃, CH₂OCH₂CH₃, C₁–C₆ alkoxy, and C₁–C₆ hydroxyalkyl; any hydrogen in the CH₂ groups in the linker is optionally substituted with H, F, Cl, Br, I, CF₃, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, C₃–C₇ cycloalkyl, C₃–C₇ heterocyclyl, OCF₃, CH₂OCH₃, CH₂CH₂OCH₃, CH₂OCH₂CH₃, or C₁–C₆ hydroxyalkyl, provided that such substitution does not result in the formation of an unstable functionality; R₉, R₁₀, R₁₁, and R₁₂ are, independently, H, C₁–C₅ straight chain alkyl, C₂–C₆ branched alkyl, R₉ and R₁₀ together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7, or R₁₁ and R₁₂ together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7; or substituents on two different atoms are connected to form a ring of size 3 to 7; R₁₃ and R₁₄ are, independently, selected from the group consisting of H, F, Cl, Br, CH₃, C₁–C₆ straight chain alkyl, and C₂–C₆ branched alkyl; and Z is selected from the group consisting of CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl, CONHS(O)₂-Heteroaryl, SO₃H, SO₂H, S(O)₂NHCO-alkyl, S(O)₂NHCO-aryl, S(O)NHCO-alkyl, S(O)NHCO-aryl, P(O)(OH)₂, P(O)OH,

provided that when m is zero, X is absent; and the compound has one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 500 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, M3, D1, D2, α1 and α2 that is more than 10 times greater than the K_(i) with regard to the H1 receptor; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 13 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 3 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 5 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) and administration of said compound to a subject does not disproportionately inhibit locomotor activity relative to the normal effects of sleep.

In one embodiment, the compound has one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 150 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, and M3, that is greater than 10 μM; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 17 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 5 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 6 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) administration of said compound to a subject does not disproportionately inhibit locomotor activity or motor tone relative to the normal effects of sleep.

The methods of the invention are used to treat a variety of subjects, including, for example, humans, companion animals, farm animals, laboratory animals and wild animals.

In one embodiment, the compound used in this method of modulating sleep is 47a, 47b, 47c, 47d, 49a, 49b, 49c, 49d, 10a, 10b, 10c, 10d, 37, 38a, 38b, 39a or 39b.

In one embodiment, the R₉ and R₁₀ and the carbon they are attached to are absent. In one embodiment, R₁₁, and R₁₂, together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7. For example, R₁₁ and R₁₂ together with the carbon to which they are attached, are connected to form a spiro 3-membered cyclopropyl ring.

In one embodiment, Z is CO₂H or tetrazole.

In one embodiment when Z is COOH, at least one of R₁–R₈, R₁₃–R₁₄ and at least one of R₉–R₁₀, R₁₁–R₁₂ are not hydrogen.

In one embodiment, R₁, R₃–R₈ and R₁₃–R₁₄ are each hydrogen and R₂ is not H, CH₃, CF₃, Cl or Br.

In another embodiment, R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ are each hydrogen, R₆ is CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br.

In one embodiment, R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ are each hydrogen, R₆ is CH₂CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br.

In another embodiment, each of R₁, R₃–R₈ and R₁₃–R₁₄ is H and R₂ is F. In one embodiment, each of R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ is H, R₆ is OCH₃, and R₂ is OCH₃.

In another embodiment, each of R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ is H, R₆ is F, and R₂ is OCH₃.

In another embodiment, when Z is COOH, R₂ is not H, F, Cl, Br, I, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, or C₃–C₇ cycloalkyl.

In another embodiment, when Z is COOH, R₇ is not H, F, Cl, Br, I, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, or C₃–C₇ cycloalkyl.

In another embodiment, when Z is COOH, neither of R₂ and R₇ is H, F, Cl, Br, I, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, or C₃–C₇ cycloalkyl.

In another embodiment, when Z is tetrazole, R₂ is not H, F, Cl, Br, I, or C₁–C₆ alkoxy.

In another embodiment, when Z is tetrazole, R₇ is not H, F, Cl, Br, I, or C₁–C₆ alkoxy.

In another embodiment, when Z is tetrazole, neither of R₂ and R₇ is H, F, Cl, Br, I, or C₁–C₆ alkoxy.

In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, and R₁₁–R₁₂ is not hydrogen.

In one embodiment, at least three of R₁–R₈ are not hydrogen. In one embodiment, at least one of R₁₃–R₁₄ is not hydrogen. In one embodiment, R₃ is not hydrogen. In one embodiment, R₇ is not hydrogen.

In one embodiment, R₉ and R₁₀ are each methyl. In another embodiment, R₉ and R₁₀ are each ethyl. In one embodiment, R₁₁ and R₁₂ are each methyl. In another embodiment, R₁₁ and R₁₂ are each ethyl.

In one embodiment, R₁₁ and R₁₂ and the carbon to which they are attached are connected to form a spiro ring of size 3–7. For example, in one embodiment, R₁₁ and R₁₂ and the carbon to which they are attached are connected to form a three-membered spiro (cyclopropyl) ring.

In one aspect, the compounds of the invention are used to modulate sleep. The sleep modulation is, e.g., by decreasing the time to sleep onset, increasing the average sleep bout length, and/or increasing the maximum sleep bout length. In another aspect, the doxepin analogs of the invention are used to promote sleep. In another aspect, the doxepin analogs of the invention are used to consolidate sleep. In another aspect, the doxepin analogs of the invention are used to treat a sleep disorder. For example, the doxepin analogs of the invention are used to treat circadian rhythm abnormality, insomnia, parasomnia, sleep apnea syndrome, narcolepsy and/or hypersomnia.

In one embodiment, the doxepin analogs of the invention are used in the treatment of a circadian rhythm abnormality, such as, for example, jet lag, shift-work disorders, delayed sleep phase syndrome, advanced sleep phase syndrome and non-24 hour sleep-wake disorder.

In another embodiment, the doxepin analogs are used in the treatment of insomnia, including, for example, extrinsic insomnia, psychophysiologic insomnia, altitude insomnia, restless leg syndrome, periodic limb movement disorder, medication-dependent insomnia, drug-dependent insomnia, alcohol-dependent insomnia and insomnia associated with mental disorders.

In one embodiment, the doxepin analogs of the invention are used to treat a parasomnia disorder, such as, e.g., somnambulism, pavor nocturnus, REM sleep behavior disorder, sleep bruxism and sleep enuresis.

In another embodiment, the doxepin analogs are used to treat a sleep apnea disorder, such as, for example, central sleep apnea, obstructive sleep apnea and mixed sleep apnea.

In another embodiment, the doxepin analogs are used to treat narcolepsy.

In another embodiment, the doxepin analogs are used to treat hypersomnia.

Pharmaceutical compositions that include a compound of Formula I or a pharmaceutically acceptable salt thereof are used in the methods of modulating sleep. In one embodiment, the compound of Formula I or pharmaceutically acceptable salt thereof is administered as a pharmaceutical composition that includes a pharmaceutically acceptable excipient.

In one embodiment, the compound of Formula I or pharmaceutically acceptable salt thereof is co-administered with one or more additional therapies.

In one embodiment, the compound of Formula I or pharmaceutically acceptable salt thereof is administered to a human, a companion animal, a farm animal, a laboratory animal, or a wild animal. In one embodiment, the compound of formula I or pharmaceutically acceptable salt thereof is administered to a human.

In another aspect, the present invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of a compound having the formula of Formula II:

or a pharmaceutically effective salt thereof, wherein m, n, and o are, individually, 0, 1, 2, 3, 4, 5, or 6; X is absent, O, S, C(O), SO or SO₂; R₁, R₂, R₃, R₆, and R₇ are, independently selected from the group consisting of H, F, Cl, Br, CF₃, CH₃, CH₂CH₃, CH(CH₃)₂, cyclopropyl, OCH₃, OCF₃, CH₂OCH₃ and CH₂OCH₂CH₃; R₉, and R₁₀, are, independently, H, C₁–C₅ straight chain alkyl; C₂–C₆ branched alkyl, or R₉ and R₁₀ together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7; R₁₃ and R₁₄ are, independently, selected from the group consisting of H, F, CH₃, C₁–C₆ straight chain alkyl, and C₂–C₆ branched alkyl; and Z is selected from the group consisting of CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl, and tetrazole, provided that when m is zero, X is absent.

These compounds have one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 500 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, M3, D1, D2, α1 and α2 that is more than 10 times greater than the K_(i) with regard to the H1 receptor; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 13 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 3 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 5 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) and administration of said compound to a subject does not disproportionately inhibit locomotor activity relative to the normal effects of sleep.

In one embodiment, the compounds of Formula II have one or more of the following characteristics:

(i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 150 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, and M3, that is greater than 10 μM; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 17 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 5 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 6 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) administration of said compound to a subject does not disproportionately inhibit locomotor activity or motor tone relative to the normal effects of sleep.

In one embodiment, R₉ and R₁₀ and the carbon they are attached to are absent. In another embodiment, R₉ and R₁₀, together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7. For example, in one embodiment, R₉ and R₁₀, together with the carbon to which they are attached, are connected to form a spiro cyclopropyl ring.

In one embodiment, Z is CO₂H or tetrazole.

In one embodiment, o is zero.

In one embodiment, at least one of R₁–R₃, R₆–R₇, R₁₃–R₁₄ and at least one of R₉–R₁₀, are not hydrogen when Z is COOH.

In one embodiment, R₁, R₃, R₆–R₇ and R₁₃–R₁₄ are each hydrogen and R₂ is not H, CH₃, CF₃, Cl or Br.

In one embodiment, R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, R₆ is CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br.

In one embodiment, R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, R₆ is CH₂CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br.

In one embodiment, each of R₁, R₃, R₆, R₇, R₁₃ and R₁₄ is H and R₂ is F.

In one embodiment, each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, R₆ is OCH₃, and R₂ is OCH₃.

In one embodiment, each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, R₆ is F, and R₂ is OCH₃.

In one embodiment, at least three of R₁–R₃, R₆–R₇, R₁₃–R₁₄ are not hydrogen.

In one embodiment, at least one of R₁₃–R₁₄ is not hydrogen.

In one embodiment, R₃ is not hydrogen. In one embodiment, R₇ is not hydrogen.

In one embodiment, R₉ and R₁₀ are each methyl. In another embodiment, R₉ and R₁₀ are each ethyl.

In one embodiment, when Z is COOH, R₂ is not H, F, Cl, Br, or CH₃.

In one embodiment, when Z is COOH, R₇ is not H, F, Cl, Br, or CH₃.

In one embodiment, when Z is COOH, neither of R₂ and R₇ is H, F, Cl, Br, or CH₃.

In one embodiment, when Z is tetrazole, R₂ is not H, F, Cl, Br, or OCH₃.

In one embodiment, when Z is tetrazole, R₇ is not H, F, Cl, Br, or OCH₃.

In one embodiment, when Z is tetrazole, neither of R₂ and R₇ is H, F, Cl, Br, or OCH₃.

In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, is not hydrogen.

In one embodiment, the sleep modulation is, e.g., decreasing the time to sleep onset, increasing the average sleep bout length, and/or increasing the maximum sleep bout length. In one embodiment, the sleep modulation treats a sleep disorder.

Pharmaceutical compositions that include a compound of Formula II or pharmaceutically acceptable salt thereof are also used in the methods of modulating sleep in a subject. In one embodiment, the compound of Formula II or pharmaceutically acceptable salt thereof is administered as a pharmaceutical composition that includes a pharmaceutically acceptable excipient.

In one embodiment, the compound of Formula II or pharmaceutically acceptable salt thereof is co-administered with one or more additional therapies.

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of a compound having the formula of Formula III:

or a pharmaceutically effective salt thereof, wherein m and n are, individually, 0, 1, 2, 3, or 4, X is absent, O, S, C(O), SO or SO₂; R₁ is H, F, Cl, Br, CF₃, CH₃, CH₂CH₃, CH(CH₂)₂, cyclopropyl, CH₂OCH₂CH₃, CH₂OCH₃, CH₂O CH₂CH₃, or OCH₃; R₂, R₃, R₆, and R₇ are, independently, selected from the group consisting of H, F, Cl, Br, CF₃, CH₃, CH₂CH₃, CH(CH₂)₂, OCH₃, CH₂OCH₃, and CH₂OCH₂CH₃; R₉, and R₁₀, are, independently, H, C₁–C₅ straight chain alkyl; C₂–C₆ branched alkyl, or R₉, and R₁₀, together with the carbon to which they are attached, are connected to form a spiro ring of size 3–7; R₁₃ and R₁₄ are, independently, selected from the group consisting of H, F, CH₃, C₁–C₆ straight chain alkyl, C₂–C₆ branched alkyl, and CH₂OCH₃; and Z is selected from the group consisting of CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl, and tetrazole, provided that when m is zero, X is absent. These compounds of Formula III have one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 500 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, M3, D1, D2, α1 and a2 that is more than 10 times greater than the K_(i) with regard to the H1 receptor; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 13 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 3 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 5 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) and administration of said compound to a subject does not disproportionately inhibit locomotor activity relative to the normal effects of sleep.

In one embodiment, the compound has one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 150 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, and M3, that is greater than 10 μM; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 17 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 5 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 6 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) administration of said compound to a subject does not disproportionately inhibit locomotor activity or motor tone relative to the normal effects of sleep.

In one embodiment, R₃ is H. In one embodiment, R₉ and R₁₀, together with the carbon to which they are attached, are connected to form a spiro ring of size 3–7. For example, in one embodiment, R₉ and R₁₀, together with the carbon to which they are attached, are connected to form a spiro cyclopropyl ring.

In one embodiment, Z is CO₂H or tetrazole.

In one embodiment, at least one of R₁–R₃, R₆–R₇, R₁₃–R₁₄ and at least one of R₉–R₁₀, are not hydrogen when Z is COOH.

In one embodiment, R₁, R₃, R₆–R₇ and R₁₃–R₁₄ are each hydrogen, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, R₆ is CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, R₆ is CH₂CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, each of R₁, R₃, R₆, R₇, R₁₃ and R₁₄ is H, and R₂ is F. In one embodiment, each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, R₆ is OCH₃, and R₂ is OCH₃. In one embodiment, each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, R₆ is F, and R₂ is OCH₃.

In one embodiment, at least three of R₁–R₃, R₆–R₇, R₁₃–R₁₄ are not hydrogen. In one embodiment, at least one of R₁₃–R₁₄ is not hydrogen. In one embodiment, R₃ is not hydrogen. In one embodiment, R₇ is not hydrogen.

In one embodiment, R₉ and R₁₀ are each methyl. In another embodiment, R₉ and R₁₀ are each ethyl.

In one embodiment, when Z is COOH, R₂ is not H, F, Cl, Br, or CH₃.

In one embodiment, when Z is COOH, R₇ is not H, F, Cl, Br, or CH₃.

In one embodiment, when Z is COOH, neither of R₂ and R₇ is H, F, Cl, Br, or CH₃.

In one embodiment, when Z is tetrazole, R₂ is not H, F, Cl, Br, or OCH₃.

In one embodiment, when Z is tetrazole, R₇ is not H, F, Cl, Br, or OCH₃.

In one embodiment, when Z is tetrazole, neither of R₂ and R₇ is H, F, Cl, Br, or OCH₃.

In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, is not hydrogen.

In one embodiment, the sleep modulation is, e.g., decreasing the time to sleep onset, increasing the average sleep bout length, and/or increasing the maximum sleep bout length. In one embodiment, the sleep modulation treats a sleep disorder.

In one embodiment, the compound of Formula III or pharmaceutically acceptable salt thereof is administered as a pharmaceutical composition that includes a pharmaceutically acceptable excipient.

Pharmaceutical compositions that include a compound of Formula III or pharmaceutically acceptable salt thereof are also used in the methods of modulating sleep according to the invention.

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of a compound having the formula of Formula IV:

or a pharmaceutically effective salt thereof wherein t is 0, 1, 2, 3, 4, 5, or 6; R₂ and R₆ are, independently, H, F, Cl, Br, CF₃, CH₃, OH, OCH₃, CH₂OCH₃, or CH₂OCH₂CH₃; R₉–R₁₀ are H, CH₃ CH₂CH₃, or R₉ and R₁₀, together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7; and Z is CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl or tetrazole, provided that when Z is COOH, t does not equal zero. These compounds of Formula IV have one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 500 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, M3, D1, D2, α1 and α2 that is more than 10 times greater than the K_(i) with regard to the H1 receptor; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 13 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 3 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 5 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) and administration of said compound to a subject does not disproportionately inhibit locomotor activity relative to the normal effects of sleep.

In one embodiment, the compound has one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 150 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, and M3, that is greater than 10 μM; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 17 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 5 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 6 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) administration of said compound to a subject does not disproportionately inhibit locomotor activity or motor tone relative to the normal effects of sleep.

In one embodiment, the compound of Formula IV is IVa, IVb, IVc, or IVd. In one embodiment, R₉ and R₁₀ together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7. For example, in one embodiment, R₉ and R₁₀ together with the carbon to which they are attached, are connected to form a spiro 3-membered cyclopropyl ring.

In one embodiment, Z is CO₂H or tetrazole.

In one embodiment, at least one of R₂, and R₆ and at least one of R₉–R₁₀, are not hydrogen when Z is COOH. In one embodiment, R₆ is hydrogen, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₆ is CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₆ is CH₂CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₆ is H, and R₂ is F. In one embodiment, R₆ is OCH₃, and R₂ is OCH₃. In one embodiment, R₆ is F, and R₂ is OCH₃.

In one embodiment, R₉ and R₁₀ are each methyl. In another embodiment, R₉ and R₁₀ are each ethyl.

In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, is not hydrogen.

In one embodiment, the sleep modulation is, e.g., decreasing the time to sleep onset, increasing the average sleep bout length, and/or increasing the maximum sleep bout length. In one embodiment, the sleep modulation treats a sleep disorder.

In one embodiment, the compound of Formula IV or pharmaceutically acceptable salt thereof is administered as a pharmaceutical composition that includes a pharmaceutically acceptable excipient.

Pharmaceutical compositions that include a compound of Formula III or pharmaceutically acceptable salt thereof are also used in the methods of modulating sleep according to the invention.

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of compound 10a:

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of compound 47a:

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of compound 47b:

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of compound 49a:

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of compound 49b:

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of compound 37:

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of compound 38a:

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of compound 38b:

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of compound 39a:

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of compound 39b:

In another aspect, the invention provides a compound according to Formula I:

or a pharmaceutically effective salt thereof, wherein m n, o, p, q are, individually, 0, 1, 2, 3, 4, 5, or 6; X and Y are, individually, absent, O, S, C(O), SO or SO₂; R₁, R₂, R₃, R₄, R₅, R₆, R₇, and R₈ are, independently selected from the group consisting of H, F, Cl, Br, I, CF₃, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, C₃–C₇ cycloalkyl, C₃–C₇ heterocyclyl, OCH₃, OCF₃, CH₂OCH₃, CH₂CH₂OCH₃, CH₂OCH₂CH₃, and C₁–C₆ hydroxyalkyl; any hydrogen in the CH₂ groups in the linker is optionally substituted with H, F, Cl, Br, I, CF₃, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, C₃–C₇ cycloalkyl, C₃–C₇ heterocyclyl, OCH₃, OCF₃, CH₂OCH₃, CH₂CH₂OCH₃, CH₂OCH₂CH₃, or C₁–C₆ hydroxyalkyl, provided that such substitution does not result in the formation of an unstable functionality; R₉, R₁₀, R₁₁, and R₁₂ are, independently, H, C₁–C₅ straight chain alkyl, C₂–C₆ branched alkyl, R₉ and R₁₀ together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7, or R₁₁ and R₁₂ together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7; or substituents on two different atoms are connected to form a ring of size 3 to 7; R₁₃ and R₁₄ are, independently, selected from the group consisting of H, F, Cl, Br, CH₃, C₁–C₆ straight chain alkyl, and C₂–C₆ branched alkyl; and Z is selected from the group consisting of CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl, CONHS(O)₂-Heteroaryl, SO₃H, SO₂H, S(O)₂NHCO-alkyl, S(O)₂NHCO-aryl, S(O)NHCO-alkyl, S(O)NHCO-aryl, P(O)(OH)₂, P(O)OH,

provided that when m is zero, X is absent.

In one embodiment, the compound has one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 500 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, M3, D1, D2, α1 and α2 that is more than 10 times greater than the K_(i) with regard to the H1 receptor; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 13 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 3 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 5 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) and administration of said compound to a subject does not disproportionately inhibit locomotor activity relative to the normal effects of sleep.

In one embodiment, the compound has one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 150 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, and M3, that is greater than 10 μM; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 17 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 5 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 6 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) administration of said compound to a subject does not disproportionately inhibit locomotor activity or motor tone relative to the normal effects of sleep.

The compounds of the invention are used to treat a variety of subjects, including, for example, humans, companion animals, farm animals, laboratory animals and wild animals.

In one embodiment, the compound used in a method of modulating sleep is 47a, 47b; 47c, 47d, 49a, 49b, 49c, 49d, 10a, 10b, 10c, 10d, 37, 38a, 38b, 39a or 39b.

In one embodiment, the R₉ and R₁₀ and the carbon they are attached to are absent. In one embodiment, R₁₁ and R₁₂, together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7. For example, R₁₁ and R₁₂ together with the carbon to which they are attached, are connected to form a spiro 3-membered cyclopropyl ring.

In one embodiment, Z is CO₂H or tetrazole.

In one embodiment where Z is COOH, at least one of R₁–R₈, R₁₃–R₁₄ and at least one of R₉–R₁₀, R₁₁–R₁₂ are not hydrogen.

In one embodiment, R₁, R₃–R₈ and R₁₃–R₁₄ are each hydrogen and R₂ is not H, CH₃, CF₃, Cl or Br. In another embodiment, R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ are each hydrogen, R₆ is CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ are each hydrogen, R₆ is CH₂CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In another embodiment, each of R₁, R₃–R₈ and R₁₃–R₁₄ is H and R₂ is F. In one embodiment, each of R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ is H, R₆ is OCH₃, and R₂ is OCH₃. In another embodiment, each of R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ is H, R₆ is F, and R₂ is OCH₃.

In one embodiment, at least three of R₁–R₈ are not hydrogen. In one embodiment, at least one of R₁₃–R₁₄ is not hydrogen. In one embodiment, R₃ is not hydrogen. In one embodiment, R₇ is not hydrogen.

In one embodiment, R₉ and R₁₀ are each methyl. In another embodiment, R₉ and R₁₀ are each ethyl. In one embodiment, R₁₁ and R₁₂ are each ethyl. In another embodiment, R₁₁ and R₁₂ are each ethyl.

In one embodiment, R₁₁ and R₁₂ and the carbon to which they are attached are connected to form a Spiro ring of size 3–7. For example, in one embodiment, R₁₁ and R₁₂ and the carbon to which they are attached are connected to form a three-membered Spiro (cyclopropyl) ring.

In another embodiment, when Z is COOH, R₂ is not H, F, Cl, Br, I, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, or C₃–C₇ cycloalkyl.

In another embodiment, when Z is COOH, R₇ is not H, F, Cl, Br, I, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, or C₃–C₇ cycloalkyl.

In another embodiment, when Z is COOH, neither of R₂ and R₇ is H, F, Cl, Br, I, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, or C₃–C₇ cycloalkyl.

In another embodiment, when Z is tetrazole, R₂ is not H, F, Cl, Br, I, or C₁–C₆ alkoxy.

In another embodiment, when Z is tetrazole, R₇ is not H, F, Cl, Br, I, or C₁–C₆ alkoxy.

In another embodiment, when Z is tetrazole, neither of R₂ and R₇ is H, F, Cl, Br, I, or C₁–C₆ alkoxy.

In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, and R₁₁–R₁₂ is not hydrogen.

In one aspect, a composition of Formula I also includes a pharmaceutically acceptable excipient.

In another aspect, the invention provides a compound of Formula II:

or a pharmaceutically effective salt thereof, wherein m, n, and o are, individually, 0, 1, 2, 3, 4, 5, or 6; X is absent, O, S, C(O), SO or SO₂; R₁, R₂, R₃, R₆, and R₇ are, independently selected from the group consisting of H, F, Cl, Br, CF₃, CH₃, CH₂CH₃, CH(CH₃)₂, cyclopropyl, OCH₃, OCF₃, CH₂OCH₃ and CH₂OCH₂CH₃; R₉, and R₁₀, are, independently, H, C₁–C₅ straight chain alkyl; C₂–C₆ branched alkyl, or R₉ and R₁₀ together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7; R₁₃ and R₁₄ are, independently, selected from the group consisting of H, F, CH₃, C₁–C₆ straight chain alkyl, and C₂–C₆ branched alkyl; and Z is selected from the group consisting of CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl, and tetrazole, provided that when m is zero, X is absent.

In one embodiment, these compounds have one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 500 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, M3, D1, D2, α1 and α2 that is more than 10 times greater than the K_(i) with regard to the H1 receptor; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 13 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 3 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 5 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) and administration of said compound to a subject does not disproportionately inhibit locomotor activity relative to the normal effects of sleep.

In one embodiment, the compounds of Formula II have one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 150 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, and M3, that is greater than 10 μM; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 17 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 5 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 6 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) administration of said compound to a subject does not disproportionately inhibit locomotor activity or motor tone relative to the normal effects of sleep.

In one embodiment, R₉ and R₁₀ and the carbon they are attached to are absent. In another embodiment, R₉ and R₁₀, together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7. For example, in one embodiment, R₉ and R₁₀, together with the carbon to which they are attached, are connected to form a spiro cyclopropyl ring.

In one embodiment, Z is CO₂H or tetrazole. In one embodiment, o is zero.

In one embodiment, at least one of R₁–R₃, R₆–R₇, R₁₃–R₁₄ and at least one of R₉–R₁₀, are not hydrogen when Z is COOH. In one embodiment, R₁, R₃, R₆–R₇ and R₁₃–R₁₄ are each hydrogen and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, R₆ is CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, R₆ is CH₂CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, each of R₁, R₃, R₆, R₇, R₁₃ and R₁₄ is H and R₂ is F. In one embodiment, each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, R₆ is OCH₃, and R₂ is OCH₃. In one embodiment, each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, R₆ is F, and R₂ is OCH₃.

In one embodiment, at least three of R₁–R₃, R₆–R₇, R₁₃–R₁₄ are not hydrogen. In one embodiment, at least one of R₁₃–R₁₄ is not hydrogen. In one embodiment, R₃ is not hydrogen. In one embodiment, R₇ is not hydrogen.

In one embodiment, R₉ and R₁₀ are each methyl. In another embodiment, R₉ and R₁₀ are each ethyl.

In one embodiment, when Z is COOH, R₂ is not H, F, Cl, Br, or CH₃.

In one embodiment, when Z is COOH, R₇ is not H, F, Cl, Br, or CH₃.

In one embodiment, when Z is COOH, neither of R₂ and R₇ is H, F, Cl, Br, or CH₃.

In one embodiment, when Z is tetrazole, R₂ is not H, F, Cl, Br, or OCH₃.

In one embodiment, when Z is tetrazole, R₇ is not H, F, Cl, Br, or OCH₃.

In one embodiment, when Z is tetrazole, neither of R₂ and R₇ is H, F, Cl, Br, or OCH₃.

In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, is not hydrogen.

In one aspect, a composition of Formula II also includes a pharmaceutically acceptable excipient.

In another aspect, the invention provides a compound of Formula III:

or a pharmaceutically effective salt thereof, wherein m and n are, individually, 0, 1, 2, 3, or 4, X is absent, O, S, C(O), SO or SO₂; R₁ is H, F, Cl, Br, CF₃, CH₃, CH₂CH₃, CH(CH₂)₂, cyclopropyl, CH₂OCH₂CH₃, CH₂OCH₃, CH₂O CH₂CH₃, or OCH₃; R₂, R₃, R₆, and R₇ are, independently, selected from the group consisting of H, F, Cl, Br, CF₃, CH₃, CH₂CH₃, CH(CH₂)₂, OCH₃, CH₂OCH₃, and CH₂OCH₂CH₃; R₉, and R₁₀, are, independently, H, C₁–C₅ straight chain alkyl; C₂–C₆ branched alkyl, or R₉, and R₁₀, together with the carbon to which they are attached, are connected to form a spiro ring of size 3–7; R₁₃ and R₁₄ are, independently, selected from the group consisting of H, F, CH₃, C₁–C₆ straight chain alkyl, C₂–C₆ branched alkyl, and CH₂OCH₃; and Z is selected from the group consisting of CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl, and tetrazole, provided that when m is zero, X is absent.

In one embodiment, these compounds of Formula III have one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 500 mM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, M3, D1, D2, α1 and α2 that is more than 10 times greater than the K_(i) with regard to the H1 receptor; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 13 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 3 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 5 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) and administration of said compound to a subject does not disproportionately inhibit locomotor activity relative to the normal effects of sleep.

In one embodiment, the compound has one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 150 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, and M3, that is greater than 10 μM; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 17 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 5 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 6 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) administration of said compound to a subject does not disproportionately inhibit locomotor activity or motor tone relative to the normal effects of sleep.

In one embodiment, R₃ is H. In one embodiment, R₉ and R₁₀, together with the carbon to which they are attached, are connected to form a spiro ring of size 3–7. For example, in one embodiment, R₉ and R₁₀, together with the carbon to which they are attached, are connected to form a spiro cyclopropyl ring.

In one embodiment, Z is CO₂H or tetrazole. In one embodiment, at least one of R₁–R₃, R₆–R₇, R₁₃–R₁₄ and at least one of R₉–R₁₀, are not hydrogen when Z is COOH.

In one embodiment, R₁, R₃, R₆–R₇ and R₁₃–R₁₄ are each hydrogen, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, R₆ is CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, R₆ is CH₂CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, each of R₁, R₃, R₆, R₇, R₁₃ and R₁₄ is H, and R₂ is F. In one embodiment, each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, R₆ is OCH₃, and R₂ is OCH₃. In one embodiment, each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, R₆ is F, and R₂ is OCH₃.

In one embodiment, at least three of R₁–R₃, R₆–R₇, R₁₃–R₁₄ are not hydrogen. In one embodiment, at least one of R₁₃–R₁₄ is not hydrogen. In one embodiment, R₃ is not hydrogen. In one embodiment, R₇ is not hydrogen.

In one embodiment, R₉ and R₁₀ are each methyl. In another embodiment, R₉ and R₁₀ are each ethyl.

In one embodiment, when Z is COOH, R₂ is not H, F, Cl, Br, or CH₃.

In one embodiment, when Z is COOH, R₇ is not H, F, Cl, Br, or CH₃.

In one embodiment, when Z is COOH, neither of R₂ and R₇ is H, F, Cl, Br, or CH₃.

In one embodiment, when Z is tetrazole, R₂ is not H, F, Cl, Br, or OCH₃.

In one embodiment, when Z is tetrazole, R₇ is not H, F, Cl, Br, or OCH₃.

In one embodiment, when Z is tetrazole, neither of R₂ and R₇ is H, F, Cl, Br, or OCH₃.

In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, is not hydrogen.

In one aspect, a composition of Formula III also includes a pharmaceutically acceptable excipient.

In another aspect, the invention provides a compound of Formula IV:

or a pharmaceutically effective salt thereof wherein t is 0, 1, 2, 3, 4, 5, or 6; R₂ and R₆ are, independently, H, F, Cl, Br, CF₃, CH₃, OH, OCH₃, CH₂OCH₃, or CH₂OCH₂CH₃; R₉–R₁₀ are H, CH₃ CH₂CH₃, or R₉ and R₁₀, together with the carbon to which they are attached, are connected to form a spiro ring of size 3 to 7; and Z is CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl or tetrazole, provided that when Z is COOH, t does not equal zero.

In one embodiment, the compounds of Formula IV have one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 500 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, M3, D1, D2, α1 and α2 that is more than 10 times greater than the K_(i) with regard to the H1 receptor; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 13 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 3 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 5 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) and administration of said compound to a subject does not disproportionately inhibit locomotor activity relative to the normal effects of sleep.

In another embodiment, the compound has one or more of the following characteristics: (i) an inhibition constant (K_(i)) with regard to H1 receptor binding of less than 150 nM; (ii) a K_(i) with regard to off target binding to an off target selected from the group consisting of M1, M2, and M3, that is greater than 10 μM; (iii) a nonREM peak time value that is greater than 55% nonREM sleep per hour by the third hour after said compound is administered to a subject; (iv) a cumulative total increase in nonREM sleep not less than 20 minutes for compound doses that produce maximum sleep consolidation; (v) a longest sleep bout that is greater than 17 minutes in duration; (vi) net longest sleep bout post treatment is greater than or equal to 5 minutes when adjusted using a baseline value obtained at least 24 hours prior to administration of said compound to a subject; (vii) an average sleep bout that is greater than 6 minutes at absolute peak; (viii) administration of said compound to a subject does not produce appreciable amounts of rebound insomnia; (ix) administration of said compound to a subject does not appreciably inhibit REM sleep; and (x) administration of said compound to a subject does not disproportionately inhibit locomotor activity or motor tone relative to the normal effects of sleep.

In one embodiment, the compound of Formula IV is IVa, IVb, IVc, or IVd. In one embodiment, R₉ and R₁₀ together with the carbon to which they are attached, are connected to form a Spiro ring of size 3 to 7. For example, in one embodiment, R₉ and R₁₀ together with the carbon to which they are attached, are connected to form a spiro 3-membered cyclopropyl ring.

In one embodiment, Z is CO₂H or tetrazole.

In one embodiment, at least one of R₂, and R₆ and at least one of R₉–R₁₀, are not hydrogen when Z is COOH. In one embodiment, R₆ is hydrogen, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₆ is CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₆ is CH₂CH₂OH, and R₂ is not H, CH₃, CF₃, Cl or Br. In one embodiment, R₆ is H, and R₂ is F. In one embodiment, R₆ is OCH₃, and R₂ is OCH₃. In one embodiment, R₆ is F, and R₂ is OCH₃.

In one embodiment, R₉ and R₁₀ are each methyl. In another embodiment, R₉ and R₁₀ are each ethyl.

In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, is not hydrogen.

In one aspect, a composition of Formula IV also includes a pharmaceutically acceptable excipient.

In one embodiment, the sleep modulation is selected from the group consisting of decreasing the time to sleep onset, increasing the average sleep bout length, and increasing the maximum sleep bout length. In one embodiment, the sleep modulation treats a sleep disorder.

Pharmaceutical compositions that include a compound of Formula IV or pharmaceutically acceptable salt thereof are also used in the methods of modulating sleep according to the invention.

In another aspect, the invention provides a compound having the structure of compound 10a:

In another aspect, the invention provides a compound having the structure of compound 47a:

In another aspect, the invention provides a compound having the structure of compound 47b:

In another aspect, the invention provides a compound having the structure of compound 49a:

In another aspect, the invention provides a compound having the structure of compound 49b:

In another aspect, the invention provides a compound having the structure of compound 37:

In another aspect, the invention provides a compound having the structure of compound 38a:

In another aspect, the invention provides a compound having the structure of compound 38b:

In another aspect, the invention provides a compound having the structure of compound 39a:

In another aspect, the invention provides a method of modulating sleep in a subject by administering a therapeutically effective amount of compound 39b:

In one aspect, the doxepin analogs of the invention are used in the treatment of a sleep disorder, including, for example, circadian rhythm abnormality, insomnia, parasomnia, sleep apnea syndrome, narcolepsy and hypersomnia.

In one embodiment, the doxepin analogs of the invention are used in the treatment of a circadian rhythm abnormality, such as, for example, jet lag, shift-work disorders, delayed sleep phase syndrome, advanced sleep phase syndrome and non-24 hour sleep-wake disorder.

In another embodiment, the doxepin analogs are used in the treatment of insomnia, including, for example, extrinsic insomnia, psychophysiologic insomnia, altitude insomnia, restless leg syndrome, periodic limb movement disorder, medication-dependent insomnia, drug-dependent insomnia, alcohol-dependent insomnia and insomnia associated with mental disorders, such as anxiety. The compounds of the invention are also used to treat sleep fragmentation associated with Parkinson's disease, Alzheimer's disease, Huntington's disease, and other dystonias.

In one embodiment, the doxepin analogs of the invention are used to treat a parasomnia disorder, such as, e.g., somnambulism, pavor nocturnus, REM sleep behavior disorder, sleep bruxism and sleep enuresis.

In another embodiment, the doxepin analogs are used to treat a sleep apnea disorder, such as, for example, central sleep apnea, obstructive sleep apnea and mixed sleep apnea.

In another embodiment, the doxepin analogs are used to treat disorders related to sleep disorders, such as, for example, fibromyalgia.

In another aspect, the doxepin analogs of the invention are used to promote sleep.

The above description sets forth rather broadly the more important features of the present invention in order that the detailed description thereof that follows may be understood, and in order that the present contributions to the art may be better appreciated. Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the examples.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph depicting typical hERG current tracings recorded at 22° C. for a vehicle control and a positive control.

FIG. 2 is a graph depicting the binding curves for compound 37 and triprolidine binding to the H1 receptor.

FIG. 3 is a graph depicting the binding curves for compound 37 and (−)-scopolamine, MeBr for the M1 receptor.

FIG. 4 is a graph depicting the binding curves for compound 37 and (−)-scopolamine, MeBr for the M2 receptor.

FIG. 5 is a graph depicting the binding curves for compound 37 and (−)-scopolamine, MeBr for the M3 receptor.

FIG. 6 is a graph depicting the sleep consolidating effects of compound 37 (HY10073) administered at a concentration of 30 mg/kg at CT-18.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The details of one or more embodiments of the invention are set forth in the accompanying description below. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. Other features, objects, and advantages of the invention will be apparent from the description. In the specification, the singular forms also include the plural unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the case of conflict, the present specification will control.

Definitions

For convenience, certain terms used in the specification, examples and appended claims are collected here.

“Treating”, includes any effect, e.g., lessening, reducing, modulating, or eliminating, that results in the improvement of the condition, disease, disorder, etc.

“Alkyl” includes saturated aliphatic groups, including straight-chain alkyl groups (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl), branched-chain alkyl groups (e.g., isopropyl, tert-butyl, isobutyl), cycloalkyl (e.g., alicyclic) groups (e.g., cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl), alkyl substituted cycloalkyl groups, and cycloalkyl substituted alkyl groups. “Alkyl” further includes alkyl groups that have oxygen, nitrogen, sulfur or phosphorous atoms replacing one or more hydrocarbon backbone carbon atoms. In certain embodiments, a straight chain or branched chain alkyl has six or fewer carbon atoms in its backbone (e.g., C₁–C₆ for straight chain, C₃–C₆ for branched chain), and more preferably four or fewer. Likewise, preferred cycloalkyls have from three to eight carbon atoms in their ring structure, and more preferably have five or six carbons in the ring structure. “C₁–C₆” includes alkyl groups containing one to six carbon atoms.

The term “alkyl” also includes both “unsubstituted alkyls” and “substituted alkyls”, the latter of which refers to alkyl moieties having substituents replacing a hydrogen on one or more carbons of the hydrocarbon backbone. Such substituents can include, for example, alkyl, alkenyl, alkynyl, halogen, hydroxyl, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carboxylate, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkylthiocarbonyl, alkoxyl, phosphate, phosphonato, phosphinato, cyano, amino (including alkylamino, dialkylamino, arylamino, diarylamino, and alkylarylamino), acylamino (including alkylcarbonylamino, arylcarbonylamino, carbamoyl and ureido), amidino, imino, sulfhydryl, alkylthio, arylthio, thiocarboxylate, sulfates, alkylsulfinyl, sulfonato, sulfamoyl, sulfonamido, nitro, trifluoromethyl, cyano, azido, heterocyclyl, alkylaryl, or an aromatic or heteroaromatic moiety. Cycloalkyls can be further substituted, e.g., with the substituents described above. An “alkylaryl” or an “aralkyl” moiety is an alkyl substituted with an aryl (e.g., phenylmethyl (benzyl)). “Alkyl” also includes the side chains of natural and unnatural amino acids.

“Aryl” includes groups with aromaticity, including 5- and 6-membered “unconjugated”, or single-ring, aromatic groups that may include from zero to four heteroatoms, as well as “conjugated”, or multicyclic, systems with at least one aromatic ring. Examples of aryl groups include benzene, phenyl, pyrrole, furan, thiophene, thiazole, isothiazole, imidazole, triazole, tetrazole, pyrazole, oxazole, isooxazole, pyridine, pyrazine, pyridazine, and pyrimidine, and the like. Furthermore, the term “aryl” includes multicyclic aryl groups, e.g., tricyclic, bicyclic, e.g., naphthalene, benzoxazole, benzodioxazole, benzothiazole, benzoimidazole, benzothiophene, methylenedioxyphenyl, quinoline, isoquinoline, napthridine, indole, benzofuran, purine, benzofuran, deazapurine, or indolizine. Those aryl groups having heteroatoms in the ring structure may also be referred to as “aryl heterocycles”, “heterocycles,” “heteroaryls” or “heteroaromatics”. The aromatic ring can be substituted at one or more ring positions with such substituents as described above, as for example, halogen, hydroxyl, alkoxy, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carboxylate, alkylcarbonyl, alkylaminocarbonyl, aralkylaminocarbonyl, alkenylaminocarbonyl, alkylcarbonyl, arylcarbonyl, aralkylcarbonyl, alkenylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylthiocarbonyl, phosphate, phosphonato, phosphinato, cyano, amino (including alkylamino, dialkylamino, arylamino, diarylamino, and alkylarylamino), acylamino (including alkylcarbonylamino, arylcarbonylamino, carbamoyl and ureido), amidino, imino, sulfhydryl, alkylthio, arylthio, thiocarboxylate, sulfates, alkylsulfinyl, sulfonato, sulfamoyl, sulfonamido, nitro, trifluoromethyl, cyano, azido, heterocyclyl, alkylaryl, or an aromatic or heteroaromatic moiety. Aryl groups can also be fused or bridged with alicyclic or heterocyclic rings, which are not aromatic so as to form a multicyclic system (e.g., tetralin, methylenedioxyphenyl).

“Alkenyl” includes unsaturated aliphatic groups analogous in length and possible substitution to the alkyls described above, but that contain at least one double bond. For example, the term “alkenyl” includes straight-chain alkenyl groups (e.g., ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl), branched-chain alkenyl groups, cycloalkenyl (e.g., alicyclic) groups (e.g., cyclopropenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl), alkyl or alkenyl substituted cycloalkenyl groups, and cycloalkyl or cycloalkenyl substituted alkenyl groups. The term “alkenyl” further includes alkenyl groups, which include oxygen, nitrogen, sulfur or phosphorous atoms replacing one or more hydrocarbon backbone carbons. In certain embodiments, a straight chain or branched chain alkenyl group has six or fewer carbon atoms in its backbone (e.g., C₂–C₆ for straight chain, C₃–C₆ for branched chain.) Likewise, cycloalkenyl groups may have from three to eight carbon atoms in their ring structure, and more preferably have five or six carbons in the ring structure. The term “C₂–C₆” includes alkenyl groups containing two to six carbon atoms.

The term “alkenyl” also includes both “unsubstituted alkenyls” and “substituted alkenyls”, the latter of which refers to alkenyl moieties having substituents replacing a hydrogen on one or more hydrocarbon backbone carbon atoms. Such substituents can include, for example, alkyl groups, alkynyl groups, halogens, hydroxyl, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carboxylate, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkylthiocarbonyl, alkoxyl, phosphate, phosphonato, phosphinato, cyano, amino (including alkylamino, dialkylamino, arylamino, diarylamino, and alkylarylamino), acylamino (including alkylcarbonylamino, arylcarbonylamino, carbamoyl and ureido), amidino, imino, sulfhydryl, alkylthio, arylthio, thiocarboxylate, sulfates, alkylsulfinyl, sulfonato, sulfamoyl, sulfonamido, nitro, trifluoromethyl, cyano, azido, heterocyclyl, alkylaryl, or an aromatic or heteroaromatic moiety.

“Alkynyl” includes unsaturated aliphatic groups analogous in length and possible substitution to the alkyls described above, but which contain at least one triple bond. For example, “alkynyl” includes straight-chain alkynyl groups (e.g., ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl), branched-chain alkynyl groups, and cycloalkyl or cycloalkenyl substituted alkynyl groups. The term “alkynyl” further includes alkynyl groups having oxygen, nitrogen, sulfur or phosphorous atoms replacing one or more hydrocarbon backbone carbons. In certain embodiments, a straight chain or branched chain alkynyl group has six or fewer carbon atoms in its backbone (e.g., C₂–C₆ for straight chain, C₃–C₆ for branched chain). The term “C₂–C₆” includes alkynyl groups containing two to six carbon atoms.

The term “alkynyl” also includes both “unsubstituted alkynyls” and “substituted alkynyls”, the latter of which refers to alkynyl moieties having substituents replacing a hydrogen on one or more hydrocarbon backbone carbon atoms. Such substituents can include, for example, alkyl groups, alkynyl groups, halogens, hydroxyl, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carboxylate, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkylthiocarbonyl, alkoxyl, phosphate, phosphonato, phosphinato, cyano, amino (including alkylamino, dialkylamino, arylamino, diarylamino, and alkylarylamino), acylamino (including alkylcarbonylamino, arylcarbonylamino, carbamoyl and ureido), amidino, imino, sulfhydryl, alkylthio, arylthio, thiocarboxylate, sulfates, alkylsulfinyl, sulfonato, sulfamoyl, sulfonamido, nitro, trifluoromethyl, cyano, azido, heterocyclyl, alkylaryl, or an aromatic or heteroaromatic moiety.

Unless the number of carbons is otherwise specified, “lower alkyl” includes an alkyl group, as defined above, but having from one to ten, more preferably from one to six, carbon atoms in its backbone structure. “Lower alkenyl” and “lower alkynyl” have chain lengths of, for example, 2–5 carbon atoms.

“Acyl” includes compounds and moieties that contain the acyl radical (CH₃CO—) or a carbonyl group. “Substituted acyl” includes acyl groups where one or more of the hydrogen atoms are replaced by for example, alkyl groups, alkynyl groups, halogens, hydroxyl, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carboxylate, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkylthiocarbonyl, alkoxyl, phosphate, phosphonato, phosphinato, cyano, amino (including alkylamino, dialkylamino, arylamino, diarylamino, and alkylarylamino), acylamino (including alkylcarbonylamino, arylcarbonylamino, carbamoyl and ureido), amidino, imino, sulflhydryl, alkylthio, arylthio, thiocarboxylate, sulfates, alkylsulfinyl, sulfonato, sulfamoyl, sulfonamido, nitro, trifluoromethyl, cyano, azido, heterocyclyl, alkylaryl, or an aromatic or heteroaromatic moiety.

“Acylamino” includes moieties wherein an acyl moiety is bonded to an amino group. For example, the term includes alkylcarbonylamino, arylcarbonylamino, carbamoyl and ureido groups.

“Aroyl” includes compounds and moieties with an aryl or heteroaromatic moiety bound to a carbonyl group. Examples of aroyl groups include phenylcarboxy, naphthyl carboxy, etc. “Alkoxyalkyl”, “alkylaminoalkyl” and “thioalkoxyalkyl” include alkyl groups, as described above, which further include oxygen, nitrogen or sulfur atoms replacing one or more hydrocarbon backbone carbon atoms, e.g., oxygen, nitrogen or sulfur atoms.

The term “alkoxy” or “alkoxyl” includes substituted and unsubstituted alkyl, alkenyl, and alkynyl groups covalently linked to an oxygen atom. Examples of alkoxy groups (or alkoxyl radicals) include methoxy, ethoxy, isopropyloxy, propoxy, butoxy, and pentoxy groups. Examples of substituted alkoxy groups include halogenated alkoxy groups. The alkoxy groups can be substituted with groups such as alkenyl, alkynyl, halogen, hydroxyl, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carboxylate, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkylthiocarbonyl, alkoxyl, phosphate, phosphonato, phosphinato, cyano, amino (including alkylamino, dialkylamino, arylamino, diarylamino, and alkylarylamino), acylamino (including alkylcarbonylamino, arylcarbonylamino, carbamoyl and ureido), amidino, imino, sulfhydryl, alkylthio, arylthio, thiocarboxylate, sulfates, alkylsulfinyl, sulfonato, sulfamoyl, sulfonamido, nitro, trifluoromethyl, cyano, azido, heterocyclyl, alkylaryl, or an aromatic or heteroaromatic moieties. Examples of halogen substituted alkoxy groups include, but are not limited to, fluoromethoxy, difluoromethoxy, trifluoromethoxy, chloromethoxy, dichloromethoxy, and trichloromethoxy.

The terms “heterocyclyl” or “heterocyclic group” include closed ring structures, e.g., 3- to 10-, or 4- to 7-membered rings, which include one or more heteroatoms. “Heteroatom” includes atoms of any element other than carbon or hydrogen. Examples of heteroatoms include nitrogen, oxygen, sulfur and phosphorus.

Heterocyclyl groups can be saturated or unsaturated and include pyrrolidine, oxolane, thiolane, piperidine, piperazine, morpholine, lactones, lactams such as azetidinones and pyrrolidinones, sultams, and sultones. Heterocyclic groups such as pyrrole and furan can have aromatic character. They include fused ring structures such as quinoline and isoquinoline. Other examples of heterocyclic groups include pyridine and purine. The heterocyclic ring can be substituted at one or more positions with such substituents as described above, as for example, halogen, hydroxyl, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carboxylate, alkylcarbonyl, alkoxycarbonyl, aminocarbonyl, alkylthiocarbonyl, alkoxyl, phosphate, phosphonato, phosphinato, cyano, amino (including alkyl amino, dialkylamino, arylamino, diarylamino, and alkylarylamino), acylamino (including alkylcarbonylamino, arylcarbonylamino, carbamoyl and ureido), amidino, imino, sulfhydryl, alkylthio, arylthio, thiocarboxylate, sulfates, sulfonato, sulfamoyl, sulfonamido, nitro, trifluoromethyl, cyano, azido, heterocyclyl, or an aromatic or heteroaromatic moiety. Heterocyclic groups can also be substituted at one or more constituent atoms with, for example, a lower alkyl, a lower alkenyl, a lower alkoxy, a lower alkylthio, a lower alkylamino, a lower alkylcarboxyl, a nitro, a hydroxyl, —CF₃, or —CN, or the like.

The term “thiocarbonyl” or “thiocarboxy” includes compounds and moieties which contain a carbon connected with a double bond to a sulfur atom.

The term “ether” includes compounds or moieties which contain an oxygen bonded to two different carbon atoms or heteroatoms. For example, the term includes “alkoxyalkyl” which refers to an alkyl, alkenyl, or alkynyl group covalently bonded to an oxygen atom which is covalently bonded to another alkyl group.

The term “ester” includes compounds and moieties which contain a carbon or a heteroatom bound to an oxygen atom which is bonded to the carbon of a carbonyl group. The term “ester” includes alkoxycarboxy groups such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, etc. The alkyl, alkenyl, or alkynyl groups are as defined above.

The term “thioether” includes compounds and moieties which contain a sulfur atom bonded to two different carbon or heteroatoms. Examples of thioethers include, but are not limited to alkthioalkyls, alkthioalkenyls, and alkthioalkynyls. The term “alkthioalkyls” include compounds with an alkyl, alkenyl, or alkynyl group bonded to a sulfur atom which is bonded to an alkyl group. Similarly, the term “alkthioalkenyls” and alkthioalkynyls” refer to compounds or moieties wherein an alkyl, alkenyl, or alkynyl group is bonded to a sulfur atom which is covalently bonded to an alkynyl group.

The term “hydroxy” or “hydroxyl” includes groups with an —OH or —O.

The term “halogen” includes fluorine, bromine, chlorine, iodine, etc. The term “perhalogenated” generally refers to a moiety wherein all hydrogens are replaced by halogen atoms.

“Polycyclyl” or “polycyclic radical” refers to two or more cyclic rings (e.g., cycloalkyls, cycloalkenyls, cycloalkynyls, aryls and/or heterocyclyls) in which two or more carbons are common to two adjoining rings. Rings that are joined through non-adjacent atoms are termed “bridged” rings. Each of the rings of the polycycle can be substituted with such substituents as described above, as for example, halogen, hydroxyl, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, carboxylate, alkylcarbonyl, alkoxycarbonyl, alkylaminocarbonyl, aralkylaminocarbonyl, alkenylaminocarbonyl, alkylcarbonyl, arylcarbonyl, aralkylcarbonyl, alkenylcarbonyl, aminocarbonyl, alkylthiocarbonyl, alkoxyl, phosphate, phosphonato, phosphinato, cyano, amino (including alkylamino, dialkylamino, arylamino, diarylamino, and alkylarylamino), acylamino (including alkylcarbonylamino, arylcarbonylamino, carbamoyl and ureido), amidino, imino, sulfhydryl, alkylthio, arylthio, thiocarboxylate, sulfates, alkylsulfinyl, sulfonato, sulfamoyl, sulfonamido, nitro, trifluoromethyl, cyano, azido, heterocyclyl, alkyl, alkylaryl, or an aromatic or heteroaromatic moiety.

An “anionic group,” as used herein, refers to a group that is negatively charged at physiological pH. Preferred anionic groups include carboxylate, sulfate, sulfonate, sulfinate, sulfamate, tetrazolyl, phosphate, phosphonate, phosphinate, or phosphorothioate or functional equivalents thereof. “Functional equivalents” of anionic groups are intended to include bioisosteres, e.g., bioisosteres of a carboxylate group. Bioisosteres encompass both classical bioisosteric equivalents and non-classical bioisosteric equivalents. Classical and non-classical bioisosteres are known in the art (see, e.g., Silverman, R. B. The Organic Chemistry of Drug Design and Drug Action, Academic Press, Inc.: San Diego, Calif., 1992, pp. 19–23). A particularly preferred anionic group is a carboxylate.

The term “unstable functionality” refers to a substitution pattern that contains a labile linkage, e.g., a functionality or bond that is susceptible to hydrolysis or cleavage under physiological conditions (e.g., aqueous solutions in the neutral pH range). Examples of unstable functionalities include acetals and ketals.

The terms “crystal polymorphs” or “polymorphs” refer to the existence of more than one crystal form for a compound, salt or solvate thereof. Crystal polymorphs of the doxepin-analog compounds are prepared by crystallization under different conditions.

It will be noted that the structure of some of the compounds of the invention includes asymmetric carbon atoms. It is to be understood accordingly that the isomers arising from such asymmetry (e.g., all enantiomers and diastereomers) are included within the scope of the invention, unless indicated otherwise. Such isomers can be obtained in substantially pure form by classical separation techniques and by stereochemically controlled synthesis. Furthermore, the structures and other compounds and moieties discussed in this application also include all tautomers thereof. Alkenes can include either the E- or Z-geometry, where appropriate.

Further, the structures and other compounds discussed in this application include all atropic isomers thereof. Atropic isomers are a type of stereoisomer in which the atoms of two isomers are arranged differently in space. Atropic isomers owe their existence to a restricted rotation caused by hindrance of rotation of large groups about a central bond. Such atropic isomers typically exist as a mixture, however as a result of recent advances in chromatography techniques, it has been possible to separate mixtures of two atropic isomers in select cases.

The language “doxepin-like compounds” or “doxepin-analog compounds” “doxepin-like compounds” or “doxepin derivative compounds” is intended to include analogs of doxepin or antihistamines that include two aryl groups linked to the same atom that are linked through a tricyclic ring system, e.g. a seven membered ring (i.e., similar to that of doxepin) linked to a double bond to position 4 of a piperidine ring.

As used herein, the term “analog” refers to a chemical compound that is structurally similar to another but differs slightly in composition (as in the replacement of one atom by an atom of a different element or in the presence of a particular functional group, or the replacement of one functional group by another functional group). Thus, an analog is a compound that is similar or comparable in function and appearance, but not in structure or origin to the reference compound. For example, the reference compound can be a reference antihistamine such as doxepin, and an analog is a substance possessing a chemical structure or chemical properties similar to those of the reference antihistamine.

As defined herein, the term “derivative”, e.g., in the term “doxepin derivatives”, refers to compounds that have a common core structure, and are substituted with various groups as described herein. For example, all of the compounds represented by formulae I–VIc are doxepin derivatives, and have one of formulae I–VIc as a common core.

The term “antihistamine” refers to a compound that binds to a H1 receptor and blocks the action of histamine.

As used herein, the term “sleep disorder” includes conditions recognized by one skilled in the art as sleep disorders, for example, conditions known in the art or conditions that are proposed to be sleep disorders or discovered to be sleep disorders. A sleep disorder also arises in a subject that has other medical disorders, diseases, or injuries, or in a subject being treated with other medications or medical treatments, where the subject, as a result, has difficulty falling asleep and/or remaining asleep, or experiences unrefreshing sleep, e.g., the subject experiences sleep deprivation.

The term “treating a sleep disorder” also includes treating a sleep disorder component of other disorders, such as CNS disorders (e.g., mental or neurological disorders such as anxiety). Additionally, the term “treating a sleep disorder” includes the beneficial effect of ameliorating other symptoms associated with the disorder.

The term “nonREM peak sleep time” is defined as an absolute peak amount of nonREM sleep per hour post treatment, with drug administration occurring at Circadian Time (CT) 18, which is 6 hours after lights off in a nocturnal laboratory rat when housed in a LD 12:12 (12-hours light and 12 hours dark) light-dark cycle. The nominal criteria of 55% nonREM sleep per hour is equivalent to 33 minutes of nonREM sleep per hour.

As used herein, the term “cumulative nonREM sleep” is defined as the net total aggregate increase in the number of minutes of nonREM sleep, measured through out the entire duration of a drug's soporific effect, which typically, but not always occurs in the first 6 hours post-treatment, adjusted for the net total aggregate number of minutes of nonREM sleep that occurred during the corresponding non-treatment baseline times of day recorded 24 hours earlier, relative to like vehicle control treatment.

As defined herein, the term “sleep bout” refers to a discrete episode of continuous or near continuous sleep, comprised of nonREM sleep, REM sleep, or both nonREM and REM sleep stages, delimited prior and after the episode by greater than two contiguous 10 second epochs of wakefulness.

As used herein, the term “longest sleep bout length” is defined as the total number of minutes an animal remains asleep (nonREM and/or REM sleep stages) during the single longest sleep episode or “bout” that occurred beginning in a given hour post-treatment. The “sleep bout length” measurement criteria assumes sleep is measured continuously in 10 second epochs, and is scored based upon the predominant state, computed or otherwise determined as a discrete sleep stage (where sleep stages are defined as nonREM sleep, REM sleep, or wakefulness) during the 10 second interval that defines the epoch.

As used herein, the term “sleep promotion” is defined as a decrease in the latency to sleep onset as is often, but not exclusively, measured by the Multiple Sleep Latency Test, or a decrease in the latency to return to sleep after awakening, or reduces the tendency to awaken or remain awake either spontaneously or as a response to wake-promoting ambient stimuli (e.g., noise, vibration, odor, pain, light). In general, a sleep promoting drug shortens the latency to sleep onset at desired bed time, or shortens the latency to return to sleep after night-time awakening, or may increase night-time total sleep time. A compound exhibiting these properties is said to promote sleep.

As used herein, the term “sleep consolidation” is defined as the ability to remain asleep or otherwise demonstrate persistent sleep after sleep onset, and throughout the desired sleep period, with little or no intervening wakefulness, as objectively measured by the number of night-time awakenings, sleep efficiency (number of awakenings per amount of time in bed), or number of transient arousals. In general, a sleep consolidating drug improves the ability to remain asleep by increasing the duration of continuous sleep between spontaneous episodes of wakefulness. A compound exhibiting these properties is said to consolidate sleep.

The term “average sleep bout length” is defined as the average duration (in minutes) of every sleep bout that began in a given hour, independent of the individual duration of each episode or bout.

“Rebound insomnia” is defined as period of rebound, paradoxical, or compensatory wakefulness that occurs after the sleep promoting effects of a hypnotic or soporific agent.

“REM sleep inhibition” is defined as the reduction of REM sleep time post-treatment at CT-18 (6 hours after lights-off; LD 12:12) or at CT-5 (5 hours after lights-on; LD 12:12). Compounds that reduce REM sleep time by greater than 15 minutes (relative to baseline and adjusted for vehicle treatment) when administered at either CT-18 or CT-5 are considered unacceptable.

Compared with NREM sleep or wakefulness, REM sleep causes ventilatory depression and episodic cardiovascular changes. During rebound insomnia, the physiological effects of REM sleep are magnified and interrupt the normal sleep cycles.

As defined herein, “disproportionate locomotor activity inhibition” is a reduction of locomotor activity that exceeds the normal and expected reduction in behavioral activity attributable to sleep.

“Combination therapy” (or “co-therapy”) includes the administration of a compound of the invention and at least a second agent as part of a specific treatment regimen intended to provide the beneficial effect from the co-action of these therapeutic agents. The beneficial effect of the combination includes, but is not limited to, pharmacokinetic or pharmacodynamic co-action resulting from the combination of therapeutic agents. Administration of these therapeutic agents in combination typically is carried out over a defined time period (usually minutes, hours, days or weeks depending upon the combination selected). “Combination therapy” may, but generally is not, intended to encompass the administration of two or more of these therapeutic agents as part of separate monotherapy regimens that incidentally and arbitrarily result in the combinations of the present invention. “Combination therapy” is intended to embrace administration of these therapeutic agents in a sequential manner, that is, wherein each therapeutic agent is administered at a different time, as well as administration of these therapeutic agents, or at least two of the therapeutic agents, in a substantially simultaneous manner. Substantially simultaneous administration can be accomplished, for example, by administering to the subject a single capsule having a fixed ratio of each therapeutic agent or in multiple, single capsules for each of the therapeutic agents. Sequential or substantially simultaneous administration of each therapeutic agent can be effected by any appropriate route including, but not limited to, oral routes, intravenous routes, intramuscular routes, and direct absorption through mucous membrane tissues. The therapeutic agents can be administered by the same route or by different routes. For example, a first therapeutic agent of the combination selected may be administered by intravenous injection while the other therapeutic agents of the combination may be administered orally. Alternatively, for example, all therapeutic agents may be administered orally or all therapeutic agents may be administered by intravenous injection. The sequence in which the therapeutic agents are administered is not narrowly critical.

“Combination therapy” also embraces the administration of the therapeutic agents as described above in further combination with other biologically active ingredients and non-drug therapies (e.g., surgery or mechanical treatments). Where the combination therapy further comprises a non-drug treatment, the non-drug treatment may be conducted at any suitable time so long as a beneficial effect from the co-action of the combination of the therapeutic agents and non-drug treatment is achieved. For example, in appropriate cases, the beneficial effect is still achieved when the non-drug treatment is temporally removed from the administration of the therapeutic agents, perhaps by days or even weeks.

The terms “parenteral administration” and “administered parenterally” as used herein refer to modes of administration other than enteral and topical administration, usually by injection, and includes, without limitation, intravenous, intramuscular, intra-arterial, intrathecal, intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal, transtracheal, subcutaneous, subcuticular, intraarticular, subcapsular, subarachnoid, intraspinal and intrasternal injection and infusion.

The term “pulmonary” as used herein refers to any part, tissue or organ whose primary function is gas exchange with the external environment, e.g, O₂/CO₂ exchange, within a patient. “Pulmonary” typically refers to the tissues of the respiratory tract. Thus, the phrase “pulmonary administration” refers to administering the formulations described herein to any part, tissue or organ whose primary function is gas exchange with the external environment (e.g., mouth, nose, pharynx, oropharynx, laryngopharynx, larynx, trachea, carina, bronchi, bronchioles, alveoli). For purposes of the present invention, “pulmonary” also includes a tissue or cavity that is contingent to the respiratory tract, in particular, the sinuses.

An “effective amount” of a compound of the disclosed invention is the quantity which, when administered to a subject in need of treatment, ameliorates symptoms arising from a sleep disorder, e.g., results in the subject falling asleep more rapidly, results in more refreshing sleep, reduces duration or frequency of waking during a sleep period, or reduces the duration, frequency, or intensity of other dyssomnias, parasomnias. The amount of the disclosed compound to be administered to a subject will depend on the particular disorder, the mode of administration, co-administered compounds, if any, and the characteristics of the subject, such as general health, other diseases, age, sex, genotype, body weight and tolerance to drugs. The skilled artisan will be able to determine appropriate dosages depending on these and other factors.

A “pharmaceutically acceptable salt” or “salt” of the disclosed compound is a product of the disclosed compound that contains an ionic bond, and is typically produced by reacting the disclosed compound with either an acid or a base, suitable for administering to a subject.

A “pharmaceutical composition” is a formulation containing the disclosed compounds in a form suitable for administration to a subject. In a preferred embodiment, the pharmaceutical composition is in bulk or in unit dosage form. The unit dosage form is any of a variety of forms, including, for example, a capsule, an IV bag, a tablet, a single pump on an aerosol inhaler, or a vial. The quantity of active ingredient (e.g., a formulation of the disclosed compound or salts thereof) in a unit dose of composition is an effective amount and is varied according to the particular treatment involved. One skilled in the art will appreciate that it is sometimes necessary to make routine variations to the dosage depending on the age and condition of the patient. The dosage will also depend on the route of administration. A variety of routes are contemplated, including oral, pulmonary, rectal, parenteral, transdermal, subcutaneous, intravenous, intramuscular, intraperitoneal, intranasal, and the like. Dosage forms for the topical or transdermal administration of a compound of this invention include powders, sprays, ointments, pastes, creams, lotions, gels, solutions, patches and inhalants. In a preferred embodiment, the active compound is mixed under sterile conditions with a pharmaceutically acceptable carrier, and with any preservatives, buffers, or propellants that are required.

The term “flash dose” refers to compound formulations that are rapidly dispersing dosage forms.

The term “immediate release” is defined as a release of compound from a dosage form in a relatively brief period of time, generally up to about 60 minutes. The term “modified release” is defined to include delayed release, extended release, and pulsed release. The term “pulsed release” is defined as a series of releases of drug from a dosage form. The term “sustained release” or “extended release” is defined as continuous release of a compound from a dosage form over a prolonged period.

A “subject” includes mammals, e.g., humans, companion animals (e.g., dogs, cats, birds, and the like), farm animals (e.g., cows, sheep, pigs, horses, fowl, and the like) and laboratory animals (e.g., rats, mice, guinea pigs, birds, and the like). Most preferably, the subject is human.

The invention provides a method of modulating sleep by administering an effective amount of a doxepin analog of the invention, which is a moiety that antagonizes a histamine receptor or a collection of histamine receptors.

Effective sleep modulators have certain characteristics that correspond with increased efficacy and decreased side effects. These characteristics include a desired half-life in a subject, controlled onset of desired sedative effects, and minimal to no detectable effect on psychomotor or other central nervous system (CNS) side effects (e.g., memory deficits, decreased muscle tone, drooping eyelids or drowsiness). For example, effective sleep modulators have a half life in humans of less than 7 hours, less than 6 hours, less than 5 hours, less than 4 hours, approximately 3 hours, or in the range of 3 to 7 hours.

One approach to developing an effective sleep modulator is strategically derivitizing a known compound or family of compounds with sleep modulating activity. Derivitizing may enhance one or more biological properties to allow a compound to perform in an improved manner. Examples of favorable biological properties include, but are not limited, to induction of a discrete sleep or hypnotic state, activity of the therapeutic compound for a discrete period of time, penetration through the blood brain barrier into the CNS, e.g., resulting from lipophilicity of substituents or conformational lipophilicity (i.e., lipophilicity as a result of a particular conformation, such as internal salt formation between a carboxylate anion and a protonated amine), modulation of the half-life of the therapeutic compound, an alteration of charge, an alteration of pharmacokinetics, an alteration of log P by a value of one or more, increased receptor selectivity, reduced peripheral half-life, the ability to increase dosage, increased peripheral elimination, decreased anti-muscarinic activity, decreased anti-cholinergic, and any combination thereof.

Derivitizing results in a variety of effects and alter different mechanisms of action. For example, in some circumstances, a compound containing a particular functional group, such as, e.g., an ester, carboxylic acid, or alcohol group, possesses an improved selectivity for a desired receptor versus undesired receptors when compared with a compound without this group. In other circumstances, the compound containing the particular functional group is more active as a therapeutic agent for treating sleep disorders than the corresponding compound without this group. The effect of the derivitized compound depends on the identity of the addition.

By derivitizing a compound in order to enhance favorable biological properties and decrease undesirable side effects, it is possible to implement a strategy based on potential mechanistic effects or interactions. For example, in some compounds, the presence of a carboxylic acid results in the ability to form an intramolecular ionic bond that includes the corresponding carboxylate ion, e.g., zwitterion species formation with a nitrogen atom within the compound or salt bridge formation. These interactions result in favorable biological effects such as conformational lipophilicity, i.e., increased lipophilicity as a result of a particular conformation, such as internal salt formation between a carboxylate anion and a protonated amine. Such conformational lipophilicity allows penetration through the blood brain barrier into the CNS, despite that the presence of two polar ions is generally thought to inhibit crossing of the non-polar blood-brain barrier. Another benefit of the presence of the carboxylic acid is an improved ability of the compound to bind selectively to the desired receptor.

Compounds of the invention can also be derivitized to produce prodrugs. “Prodrug” includes a precursor form of the drug which is metabolically converted in vivo to produce the active drug. The invention further contemplates the use of prodrugs which are converted in vivo to the sleep modulating compounds used in the methods of the invention (see, e.g., R. B. Silverman, 1992, “The Organic Chemistry of Drug Design and Drug Action”, Academic Press, Chp. 8). Such prodrugs can be used to alter the biodistribution (e.g., to allow compounds which would not typically cross the blood-brain barrier to cross the blood-brain barrier) or the pharmacokinetics of the sleep modulating compound. For example, an anionic group, e.g., a carboxylate, sulfate or sulfonate, can be esterified, e.g., with an alkyl group (e.g., a methyl group) or a phenyl group, to yield an ester. When the ester is administered to a subject, the ester is cleaved, enzymatically or non-enzymatically, reductively or hydrolytically, to reveal the anionic group. Such an ester can be cyclic, e.g., a cyclic sulfate or sulfone, or two or more anionic moieties may be esterified through a linking group. An anionic group can be esterified with moieties (e.g., acyloxymethyl esters) which are cleaved to reveal an intermediate sleep modulating compound which subsequently decomposes to yield the active sleep modulating compound. In one embodiment, the prodrug is a reduced form of a carboxylate, sulfate or sulfonate, e.g., an alcohol or thiol, which is oxidized in vivo to the sleep modulating compound. Furthermore, an anionic moiety can be esterified to a group which is actively transported in vivo, or which is selectively taken up by target organs.

This strategy is applied to sleep modulating compounds to improve their effectiveness and safety in clinical use. One group of compounds useful in modulating sleep is related to doxepin, which is a psychotherapeutic agent belonging to the family of compounds commonly known as tricyclic anti-depressants (“TCAs”). More specifically, doxepin is a mixture of geometric isomers of a dibenzoxepin tricyclic compound with the following chemical structures:

Doxepin is recommended for treating psychoneuroses, depression, anxiety, alcoholism, other organic diseases and psychotic depressive disorders.

The present invention relates to doxepin-like compounds and their use to modulate sleep. In general, in one aspect, the doxepin-like compounds include compounds of Formula I:

where m n, o, p, q are, individually, 0–6, the CH₂ groups are optionally branched, and any member of the alkylene linker (e.g., the portion of the molecule connecting the piperidine ring with the Z group) is substituted with one or more substituents; X and Y are, individually, absent or O, S, C(O), SO, or SO₂; R₁–R₈ are, independently, H, F, Cl, Br, I, CF₃, CH₃, or C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, C₃–C₇ heteroalkyl, C₃–C₇ cycloalkyl, C₃–C₇ cycloheteroalkyl, each of which is optionally heteroatom substituted, OCH₃, OCF₃, CH₂OCH₃, CH₂CH₂OCH₃, CH₂OCH₂CH₃, or C₁–C₆ hydroxyalkyl (branched or unbranched) and/or cyclic; any hydrogen in the CH₂ groups in the linker is optionally substituted with H, F, Cl, Br, I, CF₃, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, C₃–C₇ cycloalkyl, C₃–C₇ heterocyclyl, OCH₃, OCF₃, CH₂OCH₃, CH₂CH₂OCH₃, CH₂OCH₂CH₃, or C₁–C₆ hydroxyalkyl, provided that such substitution does not result in the formation of an unstable functionality; R₉–R₁₂ are H, C₁–C₅ straight chain or branched alkyl (optionally containing a heteroatom). Optionally, substituents on nearby atoms are connected to form a ring of size 3–7 or substituents on the same atom (i.e., geminal substituents) are connected to form a ring of size 3–7, e.g., R₉ and R₁₀ (or R₁₁ and R₁₂) are directly bonded to form a spiro ring of size 3–7; R₁₃ and R₁₄ are independently H, F, Cl, Br, CH₃, lower alkyl or cyclic lower alkyl, or R₁₃ and R₁₄ are directly bonded to form a spiro ring of size 3–7; Z is CO₂H, CONHS(O)₂-Aryl (optionally substituted), CONHS(O)₂-Alkyl (optionally substituted), CONHS(O)₂-Heteroaryl (optionally substituted), SO₃H, SO₂H, S(O)₂NHCO-alkyl, S(O)₂NHCO-aryl, S(O)NHCO-alkyl, S(O)NHCO-aryl, P(O)(OH)₂, P(O)OH, tetrazole, or

When m is zero, X is absent.

Where at least one of R₁–R₈, R₁₃–R₁₄ and at least one of R₉–R₁₀, R₁₁–R₁₂ are not hydrogen when Z is COOH. Also, when R₁, R₃–R₈ and R₁₃–R₁₄ are each hydrogen, R₂ is not H, CH₃, CF₃, Cl or Br. When R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ are each hydrogen, and R₆ is CH₂OH, R₂ is not H, CH₃, CF₃, Cl or Br. When R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ are each hydrogen, and R₆ is CH₂CH₂OH, R₂ is not H, CH₃, CF₃, Cl or Br.

When each of R₁, R₃–R₈, and R₁₃–R₁₄ is H, R₂ is preferably F. When each of R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ is H, and R₆ is OCH₃, R₂ is preferably OCH₃. When each of R₁, R₃–R₅, R₇–R₈ and R₁₃–R₁₄ is H, and R₆ is F, R₂ is preferably OCH₃.

In some embodiments, at least three of R₁–R₈ are not hydrogen. In some embodiments, at least one of R₁₃–R₁₄ is not hydrogen. In one embodiment, R₃ is not hydrogen. In another embodiment, R₇ is not hydrogen.

In some embodiments, R₉ and R₁₀ (along with the carbon they are attached to) are absent.

In some embodiments, R₉ and R₁₀ are each methyl. In some embodiments, R₉ and R₁₀ are each ethyl. In some embodiments, R₁ and R₁₂ are each methyl. In some embodiments, R₁₁ and R₁₂ are each ethyl. In other embodiments, R₉ and R₁₀ (along with the carbon they are attached to) are connected to form a spiro ring of size 3–7. In particular embodiments, R₉ and R₁₀ (along with the carbon they are attached to) are connected to form a three-membered spiro (cyclopropyl) ring. In other embodiments, R₁ and R₁₂ (along with the carbon they are attached to) are connected to form a spiro ring of size 3–7. In particular embodiments, R₁₁ and R₁₂ (along with the carbon they are attached to) are connected to form a three-membered spiro (cyclopropyl) ring.

In another embodiment, when Z is COOH, R₂ is not H, F, Cl, Br, I, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, or C₃–C₇ cycloalkyl. In another embodiment, when Z is COOH, R₇ is not H, F, Cl, Br, I, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, or C₃–C₇ cycloalkyl. In another embodiment, when Z is COOH, neither of R₂ and R₇ is H, F, Cl, Br, I, CH₃, C₂–C₆ straight chain alkyl, C₃–C₆ branched alkyl, or C₃–C₇ cycloalkyl. In another embodiment, when Z is tetrazole, R₂ is not H, F, Cl, Br, I, or C₁–C₆ alkoxy. In another embodiment, when Z is tetrazole, R₇ is not H, F, Cl, Br, I, or C₁–C₆ alkoxy. In another embodiment, when Z is tetrazole, neither of R₂ and R₇ is H, F, Cl, Br, I, or C₁–C₆ alkoxy. In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, and R₁₁–R₁₂ is not hydrogen.

In general, in another aspect, the present invention relates to doxepin-like compounds having the formula of Formula II:

where m n, and o, are, individually, 0–6, and the CH₂ groups in the linker are optionally branched; X is absent or O, S, C(O), SO, or SO₂; R₁, R₂, R₃, R₆ and R₇ are H, F, Cl, Br, CF₃, CH₃, CH₂CH₃, CH(CH₃)₂, cyclopropyl, OCH₃, OCF₃, CH₂OCH₃, or CH₂OCH₂CH₃; R₉–R₁₀ are H, C₁–C₅ straight chain or branched alkyl (optionally containing a heteroatom), and/or, together with the atom to which they are attached, are connected to form a ring of size 3–7; R₁₃ and R₁₄ are independently, H, F, CH₃, lower alkyl or cyclic lower alkyl, or R₁₃ and R₁₄ are directly bonded to form a spiro ring of size 3–7. Optionally, substituents on nearby atoms of the linker are connected to form a ring of size 3–7 or substituents on the same atom (i.e., geminal substituents) are connected to form a ring of size 3–7, e.g., are directly bonded to form a spiro ring of size 3–7. Z is CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl, or tetrazole, provided that when m is zero, X is absent.

Where at least one of R₁–R₃, R₆–R₇, R₁₃–R₁₄ and at least one of R₉–R₁₀, are not hydrogen when Z is COOH. Also, when R₁, R₃, R₆–R₇ and R₁₃–R₁₄ are each hydrogen, R₂ is not H, CH₃, CF₃, Cl or Br. When R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, and R₆ is CH₂OH, R₂ is not H, CH₃, CF₃, Cl or Br. When R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, and R₆ is CH₂CH₂OH, R₂ is not H, CH₃, CF₃, Cl or Br.

When each of R₁, R₃, R₆, R₇, R₁₃ and R₁₄ is H, R₂ is preferably F. When each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, and R₆ is OCH₃, R₂ is preferably OCH₃. When each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, and R₆ is F, R₂ is preferably OCH₃.

In some embodiments, at least three of R₁–R₃, R₆–R₇, R₁₃–R₁₄ are not hydrogen. In some embodiments, at least one of R₁₃–R₁₄ is not hydrogen. In one embodiment, R₃ is not hydrogen. In another embodiment, R₇ is not hydrogen.

In some embodiments, R₉ and R₁₀ are each methyl. In some embodiments, R₉ and R₁₀ are each ethyl. In other embodiments, R₉ and R₁₀ (along with the carbon they are attached to) are connected to form a spiro ring of size 3–7. In particular embodiments, R₉ and R₁₀ (along with the carbon they are attached to) are connected to form a three-membered spiro (cyclopropyl) ring.

In one embodiment, when Z is COOH, R₂ is not H, F, Cl, Br, or CH₃. In one embodiment, when Z is COOH, R₇ is not H, F, Cl, Br, or CH₃. In one embodiment, when Z is COOH, neither of R₂ and R₇ is H, F, Cl, Br, or CH₃. In one embodiment, when Z is tetrazole, R₂ is not H, F, Cl, Br, or OCH₃. In one embodiment, when Z is tetrazole, R₇ is not H, F, Cl, Br, or OCH₃. In one embodiment, when Z is tetrazole, neither of R₂ and R₇ is H, F, Cl, Br, or OCH₃. In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, is not hydrogen.

In general, in another aspect, the present invention relates to doxepin-like compounds having the formula of Formula III:

where m and n are, individually, 0–4, and the CH₂ moieties are optionally branched; X is absent or O, S, C(O), SO, or SO₂; R₉–R₁₀ are H, C₁–C₃ alkyl, optionally with heteroatom substitution, branching and/or connected to form a ring of size 3–5; R₁₃ and R₁₄ are independently H, F, CH₃, lower alkyl or cyclic lower alkyl, CH₂OCH₃, or R₁₃ and R₁₄ are directly bonded to form a spiro ring of size three to six; R₁ is H, F, Cl, Br, CF₃, CH₃, CH₂CH₃, CH(CH₂)₃, cyclopropyl, OCH₃, CH₂OCH₃ or CH₂OCH₂CH₃; R₂, R₃, R₆, and R₇ are, independently, H, F, Br, CF₃, CH₃, OCH₃, CH₂OCH₃ or CH₂OCH₂CH₃; Z is CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl, or tetrazole, provided that when m is zero, X is absent. Optionally, substituents on nearby atoms of the linker are connected to form a ring of size 3–7.

Where at least one of R₁–R₃, R₆–R₇, R₁₃–R₁₄ and at least one of R₉–R₁₀, are not hydrogen when Z is COOH. Also, when R₁, R₃, R₆–R₇ and R₁₃–R₁₄ are each hydrogen, R₂ is not H, CH₃, CF₃, Cl or Br. When R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, and R₆ is CH₂OH, R₂ is not H, CH₃, CF₃, Cl or Br. When R₁, R₃, R₇, R₁₃ and R₁₄ are each hydrogen, and R₆ is CH₂CH₂OH, R₂ is not H, CH₃, CF₃, Cl or Br.

When each of R₁, R₃, R₆, R₇, R₁₃ and R₁₄ is H, R₂ is preferably F. When each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, and R₆ is OCH₃, R₂ is preferably OCH₃. When each of R₁, R₃, R₇, R₁₃ and R₁₄ is H, and R₆ is F, R₂ is preferably OCH₃.

In some embodiments, at least three of R₁–R₃, R₆–R₇, R₁₃–R₁₄ are not hydrogen. In some embodiments, at least one of R₁₃–R₁₄ is not hydrogen. In one embodiment, R₃ is not hydrogen. In another embodiment, R₇ is not hydrogen.

In some embodiments, R₉ and R₁₀ are each methyl. In some embodiments, R₉ and R₁₀ are each ethyl. In other embodiments, R₉ and R₁₀ (along with the carbon they are attached to) are connected to form a spiro ring of size 3–7. In particular embodiments, R₉ and R₁₀ (along with the carbon they are attached to) are connected to form a three-membered spiro (cyclopropyl) ring.

In one embodiment, when Z is COOH, R₂ is not H, F, Cl, Br, or CH₃. In one embodiment, when Z is COOH, R₇ is not H, F, Cl, Br, or CH₃. In one embodiment, when Z is COOH, neither of R₂ and R₇ is H, F, Cl, Br, or CH₃. In one embodiment, when Z is tetrazole, R₂ is not H, F, Cl, Br, or OCH₃. In one embodiment, when Z is tetrazole, R₇ is not H, F, Cl, Br, or OCH₃. In one embodiment, when Z is tetrazole, neither of R₂ and R₇ is H, F, Cl, Br, or OCH₃. In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, is not hydrogen.

In another aspect, the present invention relates to doxepin-like compounds having the formula of Formula IV:

where t is between 0 and 6; R₂ and R₆ are, independently, H, F, Cl, Br, CF₃, CH₃, OH, OCH₃, CH₂OCH₃, CH₂OCH₂CH₃; R₉–R₁₀ are H, CH₃ or CH₂CH₃, and are optionally connected to form a spiro ring of size 3 to 7; and Z is CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl or tetrazole, provided that when Z is COOH, t is not zero.

At least one of R₂, and R₆ and at least one of R₉–R₁₀, are not hydrogen when Z is COOH. Also, when R₆ is hydrogen, R₂ is not H, CH₃, CF₃, Cl or Br. When R₆ is CH₂OH, R₂ is not H, CH₃, CF₃, Cl or Br. When R₆ is CH₂CH₂OH, R₂ is not H, CH₃, CF₃, Cl or Br.

When R₆ is H, R₂ is preferably F. When R₆ is OCH₃, R₂ is preferably OCH₃. When R₆ is F, R₂ is preferably OCH₃.

In a preferred embodiment, when Z is tetrazole, at least one of R₉–R₁₀, is not hydrogen.

In some embodiments, R₉ and R₁₀ are each methyl. In some embodiments, R₉ and R₁₀ are each ethyl. In other embodiments, R₉ and R₁₀ (along with the carbon they are attached to) are connected to form a spiro ring of size 3–7. In particular embodiments, R₉ and R₁₀ (along with the carbon they are attached to) are connected to form a three-membered spiro (cyclopropyl) ring.

For example, when R₉ and R₁₀ are methyl, compounds have the general formula IVa:

when R₉ and R₁₀ are connected to form a 3 membered Spiro ring (cyclopropyl), compounds have the general formula IVb:

when R₉ and R₁₀ are ethyl, compounds have the general formula IVc:

when R₉ and R₁₀ are ethyl, and the Cl carbons are connected to form a 3 membered spiro ring (cyclopropyl), compounds have the general formula IVd:

and when and R₉ and R₁₀ are hydrogen, compounds have the general formula IVe:

Some representative compounds of the invention are shown in Table 1.

TABLE 1 Di-, mono- and un- substituted doxepin derivatives Compound R₂ R₆ R₉, R₁₀ t size ring Z 46a F CH₃O CH₃ 1 none COOH 47a CH₃O F CH₃ 1 none COOH 47c CH₃O F CH₂CH₃ 1 none COOH 49b F H CH₃ 1 3 COOH 49a F H CH₃ 1 none COOH 49c F H CH₂CH₃ 1 none COOH 50b CH₃O H CH₃ 1 3 COOH 50a CH₃O H CH₃ 1 none COOH 51b Cl H CH₃ 1 3 COOH 52a H CH₃O CH₃ 1 none COOH 52b H CH₃O CH₃ 1 3 COOH 10a CH₃O CH₃O CH₃ 1 none COOH 48a F F CH₃ 1 none COOH 53a H F CH₃ 1 none COOH 61b F H CH₃ 2 3 COOH 62a CH₃O H CH₃ 2 none COOH 61a F H CH₃ 2 none COOH 62b CH₃O H CH₃ 2 3 COOH 70a H H CH₃ 2 none COOH 69b H H CH₃ 1 3 COOH 54a CF₃ H CH₃ 1 none COOH 64a CF₃ H CH₃ 2 none COOH 63a OH H CH₃ 2 none COOH 63b OH H CH₃ 2 3 COOH 65a H OH CH₃ 2 none COOH 65b H OH CH₃ 2 3 COOH 55b H OH CH₃ 1 3 COOH 55a H OH CH₃ 1 none COOH 56b OH H CH₃ 1 3 COOH 56a OH H CH₃ 1 none COOH 57a CH₃ H CH₃ 1 none COOH 66a CH₃ H CH₃ 2 none COOH 58a F OH CH₃ 1 none COOH 67b H CH₃O CH₃ 2 3 COOH 51a Cl H CH₃ 1 none COOH 69a H H CH₃ 1 none COOH 70b H H CH₃ 2 3 COOH 71a H H CH₃ 3 none COOH 68a Cl H CH₃ 2 none COOH 60a OH F CH₃ 1 none COOH 67a H CH₃O CH₃ 2 none COOH 59b Cl H CH₃ 2 3 COOH 69e H H H 1 — COOH 70e H H H 2 — COOH 71e H H H 0 — COOH

Some examples include:

In general, in another aspect, the present invention relates to doxepin-like compounds having the formula of Formula V:

where R₉ and R₁₀ are CH₃ or connected to form a cyclopropyl ring; R₁₃ and R₁₄ are independently F, CH₃, lower alkyl or cyclic lower alkyl, or R₁₃ and R₁₄ are directly bonded to form a spiro ring of size 3 to 7; R₁ is H, F, Cl, CF₃, CH₂CH₃, CH(CH₂)₃, cyclopropyl, OCH₃, CH₂OCH₃; R₂, R₆ and R₇ are H, F, Cl, Br, CH₃, OCH₃, CH₂OCH₃, CH₂OCH₂CH₃; Z is CO₂H, CONHS(O)₂-Aryl, CONHS(O)₂-Alkyl or tetrazole.

Where at least one of R₁, R₂, R₆, R₇, R₁₃, R₁₄ and at least one of R₉–R₁₀, are not hydrogen when Z is COOH. Also, when R₁, R₆, R₇, R₁₃, and R₁₄ are each hydrogen, R₂ is not H, CH₃, CF₃, Cl or Br. When R₁, R₇, R₁₃, and R₁₄ are each hydrogen, and R₆ is CH₂OH, R₂ is not H, CH₃, CF₃, Cl or Br. When R₁, R₇, R₁₃, and R₁₄ are each hydrogen, and R₆ is CH₂CH₂OH, R₂ is not H, CH₃, CF₃, Cl or Br.

When each of R₁, R₆, R₇, R₁₃ and R₁₄ is H, R₂ is preferably F. When each of R₁, R₇, R₁₃ and R₁₄ is H, and R₆ is OCH₃, R₂ is preferably OCH₃. When each of R₁, R₇, R₁₃ and R₁₄ is H, and R₆ is F, R₂ is preferably OCH₃.

In some embodiments, R₉ and R₁₀ are each methyl. In some embodiments, R₉ and R₁₀ are each ethyl. In other embodiments, R₅ and R₁₀ (along with the carbon they are attached to) are connected to form a spiro ring of size 3–7. In particular embodiments, R₉ and R₁₀ (along with the carbon they are attached to) are connected to form a three-membered spiro (cyclopropyl) ring.

Table 2 provides specific embodiments of di-substituted doxepin analogs having the following general formulae:

Table 2 provides specific embodiments of di-substituted doxepin analogs:

TABLE 2 Compound Substituent Number R₂ R₃ R₆ R₇ R₃, R₆  1a, b H OCH₃ F H R₂, R₇  2a, b F H H OCH₃ R₂, R₇  3a, b OCH₃ H H OCH₃ R₂, R₇  4a, b OCH₃ H H F R₂, R₇  5a, b OCH₃ H H CH₃ R₂, R₃  6a, b F OCH₃ H H R₂, R₇  7a, b F H H CH₃ R₂, R₃  8a, b OCH₃ F H H R₂, R₆  9a, b F H CH₃ H R₂, R₆ 10a, b OCH₃ H OCH₃ H R₂, R₆ 11a, b OCH₃ H CH₃ H R₃, R₆ 12a, b H OCH₃ CH₂OCH₃ H R₂, R₆ 13a, b F H CH₂OCH₃ H R₂, R₆ 14a, b OCH₃ H CH₂OCH₃ H R₂, R₆ 15a, b CH₂OCH₃ H OCH₃ H R₂, R₆ 16a, b CH₂OCH₃ H CH₂OCH₃ H R₂, R₆ 17a, b CH₃ H F H R₂, R₆ 18a, b CH₃ H CH₃ H R₂, R₆ 19a, b CH₃ H OCH₃ H R₂, R₆ 20a, b CH₃ H H F

Table 3 provides specific embodiments of tri-substituted doxepin analogs:

TABLE 3 Compound Substituent Number R₂ R₃ R₆ R₇ R₂, R₃, R₆ 21a, b F OCH₃ F H R₂, R₃, R₆ 22a, b F OCH₃ OCH₃ H R₂, R₃, R₆ 23a, b OCH₃ CH₃ OCH₃ H R₂, R₃, R₆ 24a, b OCH₃ CF₃ OCH₃ H R₂, R₃, R₆ 25a, b F OCH₃ CH₂OCH₃ H R₂, R₃, R₆ 26a, b OCH₃ H OCH₃ F R₂, R₃, R₆ 27a, b, OCH₃ F OCH₃ H R₂, R₃, R₆ 28a, b OCH₃ H F F R₂, R₃, R₆ 29a, b OCH₃ H F OCH₃

The compounds of Table 2 and Table 3 have the following chemical structures:

compounds of the invention include the following:

In general, in another aspect, the present invention relates to the use of doxepin-analogs of Formulae I–VIc to modulate sleep. Preferably, compounds of Formulae I–VIc modulate sleep with decreased side effects: e.g., the compounds do not inhibit REM sleep (consequently, sleep induced by these compounds may more closely resemble a person's natural sleep cycles), use of the compounds does not result in rebound insomnia, and/or the compounds do not inhibit locomotor activity or adversely effect body temperature.

In another aspect, the doxepin analogs of the invention are used to promote sleep. In another aspect, the doxepin analogs of the invention are used to consolidate sleep.

The preferred in vitro selection criteria for doxepin analogs of the invention are shown in Table 4.

TABLE 4 In Vitro Binding Criteria H1 Binding Ki < 500 nMolar (Primary Target) Off Target Binding Cholinergic M1, M2, M3 Ki > 10 times the measured H1 receptor Ki Dopamine D1, D2 Ki > 10 times the measured H1 receptor Ki Adrenergic α1, α2 Ki > 10 times the measured H1 receptor Ki

Preferably, the off target binding Ki is 50 times the measured H1 receptor Ki. In some embodiments, the off target binding Ki is 100 times the measured H1 receptor Ki.

In vitro binding assays are used to determine H1 binding (i.e., primary target binding) and M1, M2 and M3 binding (i.e., off target binding). These binding assays measure the ability of doxepin analogs to displace known standards from the H1, M1, M2, and M3 receptors, wherein H1 is a histamine receptor, and M1, M2, and M3 are cholinergic (muscarinic) receptors. Similar assays are performed with H1 and dopamine receptors (D1 and D2), and with H1 and adrenergic receptors (α1 and α2).

The binding studies against the histamine receptor, H1, indicate binding affinity, and therefore, the results of the binding assays are an indication of the activity of the a doxepin analog compound. The binding studies against the muscarinic receptors indicate the extent to which the compounds bind the muscarinic receptors responsible for anti-cholinergic activity of the compound. Binding to muscarinic receptors results in several undesired side effects of many known antihistamines, e.g., dry-mouth. A decrease in the binding of the compounds to the M1–M3 receptors, relative to the binding of the compound to the H1 receptor, is an indication of the greater specificity of the compound for the histamine receptor over the muscarinic receptor. Moreover, a drug with increased specificity for the histamine receptor possesses less anti-cholinergic side effects.

It should be noted, however, that some compounds which possess favorable H1 binding properties (e.g., Ki is less than 500 nM) are not effective sleep modulators. Further, some compounds which possess unfavorable H1 binding characteristics (e.g., Ki is greater than 500 nM) are effective sleep modulators. H1 binding is merely one characteristic that is useful in the evaluation of the compounds of the invention and is not necessarily indicative of sleep modulation.

The H1 binding of doxepin analogs of the invention (also referred to herein as “test compounds” or “compounds of the invention”) is determined by measuring the specific binding of a given test compound, or series of test compounds, to the H1 receptor, and comparing it with the specific binding of known standard (i.e., reference compound). Reference compounds used in this H1 binding assay include, for example, triprolidine (K_(i) 3.3 nM), chlorphenirramine (K_(i) 103.0 nM), pyrilamine (K_(i) 1.9 nM), cyproheptadine (K_(i) 8.5 nM), cimetidine (K_(i)>10,000) and dimaprit (K_(i)>10,000). (See e.g., Chang et al., J. Neurochem., 32:1653–63 (1979) (with modifications); Martinez-Mir, et al., Brain Res., 526:322–27 (1990); and Haaksme, et al., Pharmac. Ther., 47:73–104 (1990).

For example, in one embodiment of the H1 binding assay, the H1 receptor is from bovine cellular membranes, and a radioligand, [³H]Pyrilamine (15–25 Ci/mmol) at a final ligand concentration of 2.0 nM is used to detect specific binding for the H1 receptor. The assay characteristics include a K_(D) (binding affinity) of 1.3 nM and a B_(max) (receptor number) of 6.2 fmol/mg tissue (wet weight). Tripolidine (10 μM) is used as the non-specific determinant, reference compound and positive control. Binding reactions are carried out in 50 mM NA-KPO₄ (pH 7.5) at 25° C. for 60 minutes. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. The level of radioactivity trapped on the filters is measured and compared to control values to ascertain any interaction between a given test compound and the H1 binding site.

The M1 binding assay determines the M1 binding of a test compound by measuring the specific binding of a given test compound to M1 and comparing it with the specific binding of a reference compound. (See e.g., Buckley, et al., Mol. Pharmacol. 35:469–76 (1989) (with modifications)). Reference compounds used in the M1 binding assay include, for example, scopolamine, MethylBr (K_(i) 0.09 nM); 4-DAMP methiodide (K_(i) 0.27 nM); pirenzepine (K_(i) 2.60 nM); HHSID (K_(i) 5.00 nM); and methoctramine (K_(i) 29.70 nM).

For example, in one embodiment of the M1 binding assay, the M1 muscarinic receptor is a human recombinant M1 expressed in CHO cells, and a radioligand, [³H]-scopolamine, N-methyl chloride (80–100 Ci/mmol) at a final ligand concentration of 0.5 nM is used to detect specific binding for M1. The assay characteristics include a K_(D) (binding affinity) of 0.05 nM and a B_(max) (receptor number) of 4.2 pmol/mg protein. (−)-scopolamine, methyl-, bromide (methylscopolamine bromide) (1.0 μM) is used as the non-specific determinant, reference compound and positive control. Binding reactions are carried out in PBS for 60 minutes at 25° C. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. The level of radioactivity trapped on the filters is measured and compared to control values to ascertain any interaction between a given test compound and the cloned muscarinic M1 binding site.

The M2 binding assay determines the M2 binding of a test compound by measuring the specific binding of a given test compound to M2 and comparing it with the specific binding of a reference compound. (See e.g., Buckley, et al., Mol. Pharmacol. 35:469–76 (1989) (with modifications)). Reference compounds used in the M2 binding assay include, for example, scopolamine, MethylBr (K_(i) 0.3 nM); 4-DAMP methiodide (K_(i) 20.7 nM); methoctramine (K_(i) 20.460 nM); HHSID (K_(i) 212.7 nM); and pirenzepine (K_(i) 832.9 nM).

For example, in one embodiment of the M2 binding assay, the M2 muscarinic receptor is a human recombinant M2 expressed in CHO cells, and a radioligand, [³H]-scopolamine, N-methyl chloride (80–100 Ci/mmol) at a final ligand concentration of 0.5 nM is used to detect specific binding for M1. The assay characteristics include a K_(D) (binding affinity) of 0.29 nM and a B_(max) (receptor number) of 2.1 pmol/mg protein. (−)-scopolamine, methyl-, bromide (methylscopolamine bromide) (1.0 μM) is used as the non-specific determinant, reference compound and positive control. Binding reactions are carried out in PBS for 60 minutes at 25° C. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. The level of radioactivity trapped on the filters is measured and compared to control values to ascertain any interaction between a given test compound and the cloned muscarinic M2 binding site.

The M3 binding assay determines the M3 binding of a test compound by measuring the specific binding of a given test compound to M3 and comparing it with the specific binding of a reference compound. (See e.g., Buckley, et al., Mol. Pharmacol. 35:469–76 (1989) (with modifications)). Reference compounds used in the M3 binding assay include, for example, scopolamine, MethylBr (K_(i) 0.3 nM); 4-DAMP methiodide (K_(i) 0.8 nM); HHSID (K_(i) 14.5 nM); pirenzepine (K_(i) 153.3 nM); and methoctramine (K_(i) 700.0 nM).

For example, in one embodiment of the M3 binding assay, the M3 muscarinic receptor is a human recombinant M3 expressed in CHO cells, and a radioligand, [³H]-scopolamine, N-methyl chloride (80–100 Ci/mmol) at a final ligand concentration of 0.2 nM is used to detect specific binding for M1. The assay characteristics include a K_(D) (binding affinity) of 0.14 nM and a B_(max) (receptor number) of 4.0 pmol/mg protein. (−)-scopolamine, methyl-, bromide (methylscopolamine bromide) (1.0 μM) is used as the non-specific determinant, reference compound and positive control. Binding reactions are carried out in 50 mM TRIS-HCl (pH 7.4) containing 10 mM MgCl₂, 1 mM EDTA for 60 minutes at 25° C. The reaction is terminated by rapid vacuum filtration onto glass fiber filters. The level of radioactivity trapped on the filters is measured and compared to control values to ascertain any interaction between a given test compound and the cloned muscarinic M3 binding site.

Preferred in vitro selection criteria for doxepin analogs of the invention are shown in Table 5.

TABLE 5 In Vitro Binding Criteria H1 Binding (Primary Target) Ki < 150 nMolar Off Target Binding Cholinergic M1 Ki > 10 uM Cholinergic M2 Ki > 10 uM Cholinergic M3 Ki > 10 uM

H1 binding (primary target binding) and M1, M2 and M3 binding (off target binding) are determined using the H1, M1, M2 and M3 binding assays described above.

Other in vitro selection criteria for doxepin analogs of the invention includes hERG binding. Primary target binding and off target binding are determined as described above. If the test compound exhibits the desired primary target (H1) binding and primary target/off target binding ration, hERG binding (off target binding) is determined using a hERG block comparative study to evaluate the effect of a given test compound on cloned hERG channels expressed in mammalian cells. (See e.g., Brown and Rampe, Pharmaceutical News 7:15–20 (2000); Rampe et al., FEBS Lett., 417:28–32 (1997); Weirich and Antoni, Basic Res. Cardiol. 93 Suppl. 1:125–32 (1998); and Yap and Camn, Clin. Exp. Allergy, 29 Suppl 3, 174–81 (1999)).

Off target binding of hERG, the cardiac potassium channel responsible for the rapid delayed rectifier current (I_(Kr)) in human ventricles, is evaluated because inhibition of I_(Kr) is the most common cause of cardiac action potential prolongation by non-cardiac drugs. (See Brown and Rampe (2000), Weirich and Antoni (1998); and Yap and Camm (1999)). Increased action potential duration causes prolongation of the QT interval that has been associated with a dangerous ventricular arrhythmia, torsade de pointes. (Brown and Rampe (2000)).

In the hERG assay, hERG channels are expressed in a human embryonic kidney cell line (HEK293) that lacks endogenous I_(Kr). Expression in a mammalian cell line is preferable to transient expression in Xenopus oocytes, as the latter demonstrates a consistent 10–100 fold lower sensitivity to hERG channel blockers. (See, Rampe 1997).

In one embodiment of the hERG assay, the positive control (i.e., reference compound) is terfenadine (Sigma, St. Louis Mo.), which has been shown, at a concentration of 60 nM, to block hERG current by approximately 75%. Test compounds are delivered in HEPES-buffered physiological saline (HB-PS)+0.1% dimethyl sulfoxide (DMSO). Each test compound is applied at a concentration of 10 μM to the HEK293 cells expressing hERG (n≧3, where n=the number of cells). Cells are exposed to the test compound for the time necessary to reach steady-state block, but not longer than 10 minutes. The positive control (60 mM terfenadine) is applied to two cells (n≧2).

The hERG-exposed cells are then transferred to the recording chamber and superfused with HB-PS solution. The pipette solution for whole cell recordings includes potassium aspartate (130 mM), MgCl₂ (5 mM), EGTA (5 mM), ATP (4 mM), and HEPES (10 mM) at a pH adjusted to 7.2 with KOH. Onset and steady state block of hERG current due to the test compound are measured using a pulse pattern with fixed amplitudes (depolarization: +20 mV for 2 seconds; repolarization: −50 mV for 2 seconds), repeated at 10 second intervals, from a holding potential of −80 mV. Peak tail current is measured during the 2 second step to −50 mV. A steady state is maintained for at least 30 seconds before applying the test compound or positive control compound. Peak tail currents are measured until a new steady state is achieved.

Typical hERG current tracings recorded at 22° C. for a vehicle control and a positive control are shown in FIG. 1. Superimposed records in control and after application of a test compound. The lower panel shows voltage stimulus (prepulse +20 mV; test pulse, −50 mV; holding potential, −80 mV).

In addition to the preferred, most preferred and the other in vitro selection criteria described above, doxepin analogs of the invention are selected using the following preferred in vivo sleep-wake and physiological assessments:

NonREM Sleep: Doxepin analogs are selected if, in adult, male Wistar rats, (i) peak nonREM amount exceeds 55% nonREM per hour by no later than the third hour post-treatment; and (ii) the nature of this increase in nonREM sleep is such that the net cumulative total increase in nonREM sleep in the initial 6 hours post-treatment (adjusted for baseline at the corresponding circadian time 24 hours earlier, and relative to Vehicle control treatment) is not less than 20 minutes in total for compound doses that produces maximum sleep consolidation as measured by sleep bout length, when drug is delivered orally.

The term “nonREM peak sleep time” is defined as an absolute peak amount of nonREM sleep per hour post treatment, with drug administration occurring at Circadian Time (CT) 18, which is 6 hours after lights off in a nocturnal laboratory rat when housed in a LD 12:12 (12-hours light and 12 hours dark) light-dark cycle. The nominal criteria of 55% nonREM sleep per hour is equivalent to 33 minutes of nonREM sleep per hour.

As used herein, the term “cumulative nonREM sleep” is defined as the net total aggregate increase in the number of minutes of nonREM sleep, measured through out the entire duration of a drug's soporific effect, which typically, but not always occurs in the first 6 hours post-treatment, adjusted for the net total aggregate number of minutes of nonREM sleep that occurred during the corresponding non-treatment baseline times of day recorded 24 hours earlier, relative to like vehicle control treatment.

As defined herein, the term “sleep bout” refers to a discrete episode of continuous or near continuous sleep, comprised of nonREM sleep, REM sleep, or both nonREM and REM sleep stages, delimited prior and after the episode by greater than two contiguous 10 second epochs of wakefulness. The following non-limiting description illustrates this concept: WWWWSSSSWSSSSSSSWWSSSSSSSWWWW, wherein each letter represents the predominant state of arousal (S=sleep, W=wake) observed each 10 seconds. The measured sleep “bout” is 21 ten-second epochs or 3.5 minutes in duration.

Sleep Consolidation: Doxepin analogs are selected if, in adult male Wistar rats, (i) the absolute duration of longest continuous sleep episodes (i.e., “sleep bout”) post-treatment is greater than 13 minutes in duration; (ii) the net longest sleep bout post treatment is greater than or equal to 3 minutes when adjusted for baseline 24 hours earlier and calculated relative to vehicle treatment; and (iii) the mean absolute duration of every sleep bout when averaged per hour, on an hour by hour basis, is greater than or equal to 5 minutes. The aforementioned selection criteria assume that stages of sleep and wakefulness are determined continuously every 10 seconds (e.g., 10 second sleep scoring “epochs”), that sleep and wakefulness are measured polygraphically using EEG and EMG criteria, and sleep episodes (comprised of nonREM and/or REM sleep) are defined as continuous “bouts” until the episode is interrupted by greater than two contiguous 10 second epochs of wakefulness.

As used herein, the term “longest sleep bout length” is defined as the total number of minutes an animal remains asleep (nonREM and/or REM sleep stages) during the single longest sleep bout that occurred beginning in a given hour post-treatment. The “sleep bout length” measurement criteria assumes sleep is measured continuously in 10 second epochs, and is scored based upon the predominant state, computed or otherwise determined as a discrete sleep stage (where sleep stages are defined as nonREM sleep, REM sleep, or wakefulness) during the 10 second interval that defines the epoch.

The term “average sleep bout length” is defined as the average duration (in minutes) of every and all sleep episodes or bouts that began in a given hour, independent of the individual duration of each episode or bout.

Concurrently Measured Side Effects: Doxepin analogs are selected if, in adult, male Wistar rats, these compounds (i) do not produce appreciable amounts of rebound insomnia; (ii) do not appreciably inhibit REM sleep; and (iii) do not disproportionately inhibit locomotor motor activity and/or motor tone relative to the normal effects of sleep itself. The threshold definitions for these three side-effect variables are as follows:

“Rebound insomnia” is defined as period of rebound, paradoxical, or compensatory wakefulness that occurs after the sleep promoting effects of a hypnotic or soporific agent. Rebound insomnia is typically observed during the usual circadian rest phase 6–18 hours post-treatment at CT-18 (6 hours after lights-off, given LD 12:12), but can occur at any time during the initial 30 hours post-treatment. Rebound is considered unacceptable when, in the adult, male Wistar rat, excess cumulative wakefulness associated with rebound insomnia is greater than 20% of the net cumulative increase in sleep produced by the hypnotic or soporific effects of a compound.

In adult, male Wistar rats, rebound insomnia manifests as an increase in wakefulness relative to corresponding times at baseline (24 hours earlier) subsequent to a drug-induced sleep effect, and rebound insomnia is measured cumulatively. The following non-limiting description illustrates this measurement: Compound A, administered to laboratory rats at CT-18 (6 hours after lights-off, given LD 12:12), produced a 50 minute cumulative increase in sleep time (relative to baseline sleep measures 24 hours earlier) during the initial 6 hours post-treatment. After the sleep promoting effects of the compound subsided, the animals demonstrated a cumulative increase in wakefulness relative to baseline 24 hours earlier. Because the soporific effect of the compound produced 50minutes of additional sleep, a subsequent cumulative increase in wakefulness (rebound insomnia) of greater than 10 minutes total would be unacceptable.

“REM sleep inhibition” is defined as the reduction of REM sleep time post-treatment at CT-18 (6 hours after lights-off; LD 12:12) or at CT-5 (5 hours after lights-on; LD 12:12). Compounds that reduce REM sleep time by greater than 15 minutes (relative to baseline and adjusted for vehicle treatment) when administered at either CT-18 or CT-5 are considered unacceptable.

As defined herein, “disproportionate locomotor activity inhibition” is a reduction of locomotor activity that exceeds the normal and expected reduction in behavioral activity attributable to sleep. Logic dictates that if an animal is asleep, there will normally be a corresponding reduction in locomotor activity. If a hypnotic or soporific compound reduces locomotor activity levels in excess of 20% greater than that explained by sleep alone, the compound is deemed unacceptable. Locomotor activity (LMA) or motor tone may be quantified objectively using any form of behavioral locomotor activity monitor (non-specific movements, telemetry-based activity monitoring, 3-dimensional movement detection devices, wheel running activity, exploratory measures, electromyographic recording, etc.) so long as it is measured concurrently with objective sleep-wakefulness measures in the same animal.

In one embodiment, locomotor activity within the animal's cage is measured using a biotelemetry device surgically implanted in the animal's peritoneal cavity; the implantable device and associated telemetry receiver detects if and how much animal moves within the cage. Sleep and wakefulness is measured in 10 second epochs simultaneously. Counts of locomotor activity per unit time are divided by the concurrent amount of wakefulness per the same unit, yielding a “locomotor activity intensity” (LMAI) measure for that unit time. Hypnotic or soporific compounds administered at CT-18 (6 hours after lights-off; LD 12:12) that decrease locomotor activity per unit time awake by greater than 20% relative to vehicle would be judged unacceptable.

In a more preferred embodiment, the doxepin analogs of the invention are selected using the in vivo sleep-wake and physiological assessment criteria shown in Table 6:

TABLE 6 Change from baseline Absolute value relative to SCORE-2000 Value vehicle only NonREM Peak Time >55% sleep/hour Not applicable peak Cumulative Not applicable >20 minutes at ED100 NonREM for MSBL at T_(1–6) Longest Sleep Bout >17 minutes >5 minutes absolute peak Average Sleep Bout >6 minutes Not used in SAR cuts absolute peak Rebound Insomnia <20% of net Not applicable NonREM sleep gain REM Sleep not applicable not to exceed 15 Inhibition minutes, Rx at CT5 LMAI not applicable not to exceed 20% LMAI reduction

Methods for evaluating these sleep-wake and physiological assessment criteria are described above. The “absolute value” shown in second column of Table 6 refers to the value as determined for each test compound, while the “change” value shown in the third column of Table 6 reflects an adjusted value in which the absolute value is the difference from vehicle, when the vehicle values are adjusted for baseline.

In some embodiments, the longest sleep bout is greater than 13 minutes in duration. In others, it is greater than 17 minutes in duration. In some embodiments, the net longest sleep bout post treatment is greater than or equal to 3 minutes in duration. In others, it is greater than or equal to 6 minutes in duration.

Other in vivo sleep-wake and physiological assessment criteria used to select doxepin analogs of the invention include measurement of acute body temperature and latent body temperature as a change in baseline relative to vehicle. The acute body temperature change should not exceed −0.50° C., and the latent body temperature change should not exceed +0.50° C. at Time 1–6 hours. The acute body temperature (T_(1–6)) is adjusted for the corresponding baseline measured 24 hours earlier, relative to vehicle (the decrease from vehicle). The latent body temperature, measured 7–18 hours post drug treatment (T_(7–18)), is adjusted for the corresponding baseline measured 24 hours earlier, relative to vehicle (the decrease from vehicle).

The invention provides a method of modulating sleep by administering to a subject a therapeutically effective amount of a compound of Formula I–VIb or VIc or a pharmaceutically effective salt thereof. The method modulates sleep several ways including decreasing the time to sleep onset, increasing the average sleep bout length, and increasing the maximum sleep bout length.

The compounds, or pharmaceutically acceptable salts thereof, is administered orally, nasally, transdermally, pulmonary, inhalationally, buccally, sublingually, intraperintoneally, intravenously, rectally, intrapleurally, intrathecally and parenterally. In a preferred embodiment, the compound is administered orally. One skilled in the art will recognize the advantages of certain routes of administration.

The method of modulating sleep by administering to a subject a therapeutically effective amount of a compound of Formula I–VIb or VIc or a pharmaceutically effective salt thereof is used to treat a variety of sleep disorders including circadian rhythm abnormality, insomnia, parasomnia, sleep apnea syndrome, narcolepsy and hypersomnia. In a preferred embodiment, the method treats circadian rhythm abnormalities including jet lag, shift-work disorders, delayed sleep phase syndrome, advanced sleep phase syndrome and non-24 hour sleep-wake disorder. In another embodiment, the method treats insomnia including extrinsic insomnia, psychophysiologic insomnia, altitude insomnia, restless leg syndrome, periodic limb movement disorder, medication-dependent insomnia, drug-dependent insomnia, alcohol-dependent insomnia and insomnia associated with mental disorders.

In another embodiment, the method treats parasomnias including somnambulism, pavor nocturnus, REM sleep behavior disorder, sleep bruxism and sleep enuresis. In yet another embodiment, the method treats sleep apnea disorder including central sleep apnea, obstructive sleep apnea and mixed sleep apnea. Additionally, the method treats other sleep disorders such as narcolepsy or hypersomnia.

In some embodiments, a compound of Formula I–VIb or VIc is administered as a pharmaceutically acceptable salt. One skilled in the art will recognize the various methods for creating pharmaceutically acceptable salts and identifying the appropriate salt. In a preferred embodiment, the compound or pharmaceutically acceptable salt thereof is included in a pharmaceutical composition.

A “subject” includes mammals, e.g., humans, companion animals (e.g., dogs, cats, birds, and the like), farm animals (e.g., cows, sheep, pigs, horses, fowl, and the like) and laboratory animals (e.g., rats, mice, guinea pigs, birds, and the like). Most preferably, the subject is human.

A subject in need of treatment has a sleep disorder that can affect the subject's ability to fall asleep and/or remain asleep, and/or results in unrefreshing sleep.

As used herein, the term “sleep disorder” includes conditions recognized by one skilled in the art as sleep disorders, for example, conditions known in the art or conditions that are proposed to be sleep disorders or discovered to be sleep disorders. See, for example, Thorpy, M J International Classification of Sleep Disorders, Revised: Diagnostic and Coding Manual. American Sleep Disorders Association; Rochester, Minn. 1997; and ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification, National Center for Health Statistics, Hyattsville, Md.

For example, sleep disorders can be generally classed into dyssomnias, e.g., intrinsic, extrinsic, and circadian rhythm disorders; parasomnias, e.g., arousal, sleep-wake transition, and rapid eye movement (REM) associated disorders, and other parasomnias; disorders associated with mental, neurological, and other medical disorders; and other sleep disorders.

Intrinsic sleep disorders include, for example, psychophysiological insomnia, sleep state misperception, idiopathic insomnia, narcolepsy, recurrent hypersomnia, idiopathic hypersomnia, post-traumatic hypersomnia, obstructive sleep apnea syndrome, central sleep apnea syndrome, central alveolar hypoventilation syndrome, periodic limb movement disorder, and restless legs syndrome.

Extrinsic sleep disorders include, for example, inadequate sleep hygiene, environmental sleep disorder, altitude insomnia, adjustment sleep disorder, insufficient sleep syndrome, limit-setting sleep disorder, sleep-onset association disorder, food allergy insomnia, nocturnal eating (drinking) syndrome, hypnotic-dependent sleep disorder, stimulant-dependent sleep disorder, alcohol-dependent sleep disorder, and toxin-induced sleep disorder.

Circadian rhythm sleep disorders include, for example, time-zone change (jet lag) syndrome, shift work sleep disorder, irregular sleep-wake pattern, delayed sleep phase syndrome, advanced sleep phase syndrome, and non-24-hour sleep-wake disorder.

Arousal sleep disorders include, for example, confusional arousals, sleepwalking and sleep terrors.

Sleep-wake transition disorders include, for example, rhythmic movement disorder, sleep starts, sleeptalking, and nocturnal leg cramps.

REM-associated sleep disorders include, for example, nightmares, sleep paralysis, impaired sleep-related penile erections, sleep-related painful erections, REM sleep-related sinus arrest, and REM sleep behavior disorder.

Other parasomnias include, for example, sleep bruxism, sleep enuresis, sleep-related abnormal swallowing syndrome, nocturnal paroxysmal dystonia, sudden unexplained nocturnal death syndrome, primary snoring, infant sleep apnea, congenital central hypoventilation syndrome, sudden infant death syndrome, and benign neonatal sleep myoclonus.

A “sleep disorder” also arises in a subject that has other medical disorders, diseases, or injuries, or in a subject being treated with other medications or medical treatments, where the subject as a result has difficulty falling asleep and/or remaining asleep, or experiences unrefreshing sleep, e.g., the subject experiences sleep deprivation. For example, some subjects have difficulty sleeping after undergoing medical treatment for other conditions, e.g., chemotherapy or surgery, or as a result of pain or other effects of physical injuries.

It is well known in the art that certain medical disorders, for example, central nervous system (CNS) disorders, e.g. mental or neurological disorders, e.g., anxiety, can have a sleep disorder component, e.g., sleep deprivation. Thus, “treating a sleep disorder” also includes treating a sleep disorder component of other disorders, e.g., CNS disorders. Further, treating the sleep disorder component of CNS disorders can also have the beneficial effect of ameliorating other symptoms associated with the disorder. For example, in some subjects experiencing anxiety coupled with sleep deprivation, treating the sleep deprivation component also treats the anxiety component. Thus, the present invention also includes a method of treating such medical disorders.

For example, sleep disorders associated with mental disorders include psychoses, mood disorders, anxiety disorders, panic disorder, addictions, and the like. Specific mental disorders include, for example, depression, obsessive compulsive disorder, affective neurosis/disorder, depressive neurosis/disorder, anxiety neurosis; dysthymic disorder, behavior disorder, mood disorder, schizophrenia, manic depression, delirium, and alcoholism.

Sleep disorders associated with neurological disorders include, for example, cerebral degenerative disorders, dementia, parkinsonism, Huntington's disease, Alzheimer's, fatal familial insomnia, sleep related epilepsy, electrical status epilepticus of sleep, and sleep-related headaches. Sleep disorders associated with other medical disorders include, for example, sleeping sickness, nocturnal cardiac ischemia, chronic obstructive pulmonary disease, sleep-related asthma, sleep-related gastroesophageal reflux, peptic ulcer disease, and fibrositis syndrome.

In some circumstances, sleep disorders are also associated with pain, e.g., neuropathic pain associated with restless leg syndrome; migraine; hyperalgesia, fibromyalgia, pain; enhanced or exaggerated sensitivity to pain, such as hyperalgesia, causalgia and allodynia; acute pain; burn pain; atypical facial pain; neuropathic pain; back pain; complex regional pain syndromes I and II; arthritic pain; sports injury pain; pain related to infection, e.g., HIV, post-polio syndrome, and post-herpetic neuralgia; phantom limb pain; labor pain; cancer pain; post-chemotherapy pain; post-stroke pain; post-operative pain; neuralgia; conditions associated with visceral pain including irritable bowel syndrome, migraine and angina.

Other sleep disorders include, for example, short sleeper, long sleeper, subwakefillness syndrome, fragmentary myoclonus, sleep hyperhidrosis, menstrual-associated sleep disorder, pregnancy-associated sleep disorder, terrifying hypnagogic hallucinations, sleep-related neurogenic tachypnea, sleep-related laryngospasm, and sleep choking syndrome.

Insomnia is typically classed into sleep onset insomnia, where a subject takes more than 30 minutes to fall asleep; and sleep maintenance insomnia, where the subject spends more than 30 minutes awake during an expected sleep period, or, for example, waking before the desired wake-up time with difficulty or an inability to get back to sleep. The disclosed compounds are particularly effective in treating sleep onset and sleep maintenance insomnias, insomnia resulting from circadian rhythm adjustment disorders, or insomnia resulting from CNS disorders. A preferred embodiment is treating a subject for a circadian rhythm adjustment disorder. Another preferred embodiment is treating a subject for insomnia resulting from a mood disorder. In other embodiments, a subject is treated for sleep apnea, somnambulism, night terrors, restless leg syndrome, sleep onset insomnia, and sleep maintenance insomnia; or more preferably, sleep onset insomnia or sleep maintenance insomnia. The disclosed compounds are particularly effective for treating sleep onset insomnia. The disclosed compounds are also particularly effective for treating sleep maintenance insomnia.

The dosage regimen utilizing the compounds is selected in accordance with a variety of factors including type, species, age, weight, sex and medical condition of the patient; the severity of the condition to be treated; the route of administration; the renal and hepatic function of the patient; and the particular compound or salt thereof employed. An ordinarily skilled physician or veterinarian can readily determine and prescribe the effective amount of the drug required to prevent, counter or arrest the progress of the condition.

Oral dosages of the present invention, when used for the indicated effects, will range between about 0.05 to 5000 mg/day orally. Effective amounts of the disclosed compounds typically range between about 0.01 mg/kg per day and about 100 mg/kg per day, and preferably between 0.1 mg/kg per day and about 10 mg/kg/day. Techniques for administration of the disclosed compounds of the invention can be found in Remington: the Science and Practice of Pharmacy, 19^(th) edition, Mack Publishing Co., Easton, Pa. (1995).

For example, in some embodiments, an acid salt of a compound containing an amine or other basic group is obtained by reacting the compound with a suitable organic or inorganic acid, such as hydrogen chloride, hydrogen bromide, acetic acid, perchloric acid and the like. Compounds with a quaternary ammonium group also contain a counter anion such as chloride, bromide, iodide, acetate, perchlorate and the like. Other examples of such salts include hydrochlorides, hydrobromides, sulfates, methanesulfonates, nitrates, maleates, acetates, citrates, fumarates, tartrates (e.g. (+)-tartrates, (−)-tartrates or mixtures thereof including racemic mixtures), succinates, benzoates and salts with amino acids such as glutamic acid.

Salts of compounds containing a carboxylic acid or other acidic functional group are prepared by reacting with a suitable base. Such a pharmaceutically acceptable salt is made with a base which affords a pharmaceutically acceptable cation, which includes alkali metal salts (especially sodium and potassium), alkaline earth metal salts (especially calcium and magnesium), aluminum salts and ammonium salts, as well as salts made from physiologically acceptable organic bases such as trimethylamine, triethylamine, morpholine, pyridine, piperidine, picoline, dicyclohexylamine, N,N′-dibenzylethylenediamine, 2-hydroxyethylamine, bis-(2-hydroxyethyl)amine, tri-(2-hydroxyethyl)amine, procaine, dibenzylpiperidine, N-benzyl-∃-phenethylamine, dehydroabietylamine, N,N′-bisdehydroabietylamine, glucamine, N-methylglucamine, collidine, quinine, quinoline, and basic amino acid such as lysine and arginine.

In some embodiments, certain compounds and their salts also exist in the form of solvates, for example hydrates, and the present invention includes each solvate and mixtures thereof.

The disclosed compounds, and salts or solvates thereof may exist in more than one crystal form, e.g., as “crystal polymorphs” or “polymorphs”. Crystal polymorphs of the disclosed compounds are prepared by crystallization under different conditions. For example, using different solvents or different solvent mixtures for recrystallization; crystallization at different temperatures; various modes of cooling, ranging from very fast to very slow cooling during crystallization, and the like. Polymorphs are also obtained by heating or melting the disclosed compounds followed by gradual or fast cooling. The presence of polymorphs is determined by solid probe nuclear magnetic resonance spectroscopy, infrared spectroscopy, differential scanning calorimetry, powder X-ray diffraction, and other techniques known to one skilled in the art.

In an embodiment, the compounds described herein, and the pharmaceutically acceptable salts thereof are used in pharmaceutical preparations in combination with a pharmaceutically acceptable carrier or diluent. Suitable pharmaceutically acceptable carriers include inert solid fillers or diluents and sterile aqueous or organic solutions. The compounds will be present in such pharmaceutical compositions in amounts sufficient to provide the desired dosage amount in the range described herein. Techniques for formulation and administration of the disclosed compounds of the invention can be found in Remington: the Science and Practice of Pharmacy, above.

Typically, the compound is prepared for oral administration, wherein the disclosed compounds or salts thereof are combined with a suitable solid or liquid carrier or diluent to form capsules, tablets, pills, powders, syrups, solutions, suspensions and the like.

The tablets, pills, capsules, and the like contain from about 1 to about 99 weight percent of the active ingredient and a binder such as gum tragacanth, acacias, corn starch or gelatin; excipients such as dicalcium phosphate; a disintegrating agent such as corn starch, potato starch or alginic acid; a lubricant such as magnesium stearate; and/or a sweetening agent such as sucrose, lactose, saccharin, xylitol, and the like. When a dosage unit form is a capsule, it often contains, in addition to materials of the above type, a liquid carrier such as a fatty oil.

In some embodiments, various other materials are present as coatings or to modify the physical form of the dosage unit. For instance, in some embodiments, tablets are coated with shellac, sugar or both. In some embodiments, a syrup or elixir contains, in addition to the active ingredient, sucrose as a sweetening agent, methyl and propylparabens as preservatives, a dye and a flavoring such as cherry or orange flavor, and the like.

For some embodiments relating to parental administration, the disclosed compounds, or salts, solvates, or polymorphs thereof, can be combined with sterile aqueous or organic media to form injectable solutions or suspensions. Injectable compositions are preferably aqueous isotonic solutions or suspensions. The compositions may be sterilized and/or contain adjuvants, such as preserving, stabilizing, wetting or emulsifying agents, solution promoters, salts for regulating the osmotic pressure and/or buffers. In addition, they may also contain other therapeutically valuable substances. The compositions are prepared according to conventional mixing, granulating or coating methods, respectively, and contain about 0.1 to 75%, preferably about 1 to 50%, of the active ingredient.

For example, injectable solutions are produced using solvents such as sesame or peanut oil or aqueous propylene glycol, as well as aqueous solutions of water-soluble pharmaceutically-acceptable salts of the compounds. In some embodiments, dispersions are prepared in glycerol, liquid polyethylene glycols and mixtures thereof in oils. Under ordinary conditions of storage and use, these preparations contain a preservative to prevent the growth of microorganisms. The terms “parenteral administration” and “administered parenterally” as used herein means modes of administration other than enteral and topical administration, usually by injection, and includes, without limitation, intravenous, intramuscular, intraarterial, intrathecal, intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal, transtracheal, subcutaneous, subcuticular, intraarticular, subcapsular, subarachnoid, intraspinal and intrastemal injection and infusion.

For rectal administration, suitable pharmaceutical compositions are, for example, topical preparations, suppositories or enemas. Suppositories are advantageously prepared from fatty emulsions or suspensions. The compositions may be sterilized and/or contain adjuvants, such as preserving, stabilizing, wetting or emulsifying agents, solution promoters, salts for regulating the osmotic pressure and/or buffers. In addition, they may also contain other therapeutically valuable substances. The compositions are prepared according to conventional mixing, granulating or coating methods, respectively, and contain about 0.1 to 75%, preferably about 1 to 50%, of the active ingredient.

In some embodiments, the compounds are formulated to deliver the active agent by pulmonary administration, e.g., administration of an aerosol formulation containing the active agent from, for example, a manual pump spray, nebulizer or pressurized metered-dose inhaler. In some embodiments, suitable formulations of this type also include other agents, such as antistatic agents, to maintain the disclosed compounds as effective aerosols.

A drug delivery device for delivering aerosols comprises a suitable aerosol canister with a metering valve containing a pharmaceutical aerosol formulation as described and an actuator housing adapted to hold the canister and allow for drug delivery. The canister in the drug delivery device has a headspace representing greater than about 15% of the total volume of the canister. Often, the polymer intended for pulmonary administration is dissolved, suspended or emulsified in a mixture of a solvent, surfactant and propellant. The mixture is maintained under pressure in a canister that has been sealed with a metering valve.

For nasal administration, either a solid or a liquid carrier can be used. The solid carrier includes a coarse powder having particle size in the range of, for example, from about 20 to about 500 microns and such formulation is administered by rapid inhalation through the nasal passages. In some embodiments where the liquid carrier is used, the formulation is administered as a nasal spray or drops and includes oil or aqueous solutions of the active ingredients.

Also contemplated are formulations that are rapidly dispersing dosage forms, also known as “flash dose” forms. In particular, some embodiments of the present invention are formulated as compositions that release their active ingredients within a short period of time, e.g., typically less than about five minutes, preferably less than about ninety seconds, more preferably in less than about thirty seconds and most preferably in less than about ten or fifteen seconds. Such formulations are suitable for administration to a subject via a variety of routes, for example by insertion into a body cavity or application to a moist body surface or open wound.

Typically, a “flash dosage” is a solid dosage form that is administered orally, which rapidly disperses in the mouth, and hence does not require great effort in swallowing and allows the compound to be rapidly ingested or absorbed through the oral mucosal membranes. In some embodiments, suitable rapidly dispersing dosage forms are also used in other applications, including the treatment of wounds and other bodily insults and diseased states in which release of the medicament by externally supplied moisture is not possible.

“Flash dose” forms are known in the art; see for example, effervescent dosage forms and quick release coatings of insoluble microparticles in U.S. Pat. Nos. 5,578,322 and 5,607,697; freeze dried foams and liquids in U.S. Pat. Nos. 4,642,903 and 5,631,023; melt spinning of dosage forms in U.S. Pat. Nos. 4,855,326, 5,380,473 and 5,518,730; solid, free-form fabrication in U.S. Pat. No. 6,471,992; saccharide-based carrier matrix and a liquid binder in U.S. Pat. Nos. 5,587,172, 5,616,344, 6,277,406, and 5,622,719; and other forms known to the art.

The doxepin analogs of the invention are also formulated as “pulsed release” formulations, in which the analog is released from the pharmaceutical compositions in a series of releases (i.e., pulses). The doxepin analogs are also formulated as “sustained release” formulations in which the analog is continuously released from the pharmaceutical composition over a prolonged period.

Also contemplated are formulations, e.g., liquid formulations, including cyclic or acyclic encapsulating or solvating agents, e.g., cyclodextrins, polyethers, or polysaccharides (e.g., methylcellulose), or more preferably, polyanionic β-cyclodextrin derivatives with a sodium sulfonate salt group separate from the lipophilic cavity by an alkyl ether spacer group or polysaccharides. In a preferred embodiment, the agent is methylcellulose. In another preferred embodiment, the agent is a polyanionic β-cyclodextrin derivative with a sodium sulfonate salt separated from the lipophilic cavity by a butyl ether spacer group, e.g., CAPTISOL® (CyDex, Overland, Kans.). One skilled in the art can evaluate suitable agent/disclosed compound formulation ratios by preparing a solution of the agent in water, e.g., a 40% by weight solution; preparing serial dilutions, e.g. to make solutions of 20%, 10, 5%, 2.5%, 0% (control), and the like; adding an excess (compared to the amount that can be solubilized by the agent) of the disclosed compound; mixing under appropriate conditions, e.g., heating, agitation, sonication, and the like; centrifuging or filtering the resulting mixtures to obtain clear solutions; and analyzing the solutions for concentration of the disclosed compound.

In addition to the therapeutic formulations described above, a therapy including the compounds of the present invention optionally includes, co-administration with one or more additional therapies, e.g., drugs or physical or behavioral treatments (e.g., light therapy, electrical stimulation, behavior modification, cognitive therapy, circadian rhythm modification, and the like). Such a practice is referred to as “combination therapy.” The other therapy or therapies in the combination therapy include therapies recognized by one skilled in the art as desirable in combination with the compound of the invention, for example, therapies known to the art or therapies which are proposed or discovered in the art for treating sleep disorders or treating diseases associated with sleep disorders, for example, therapies for any of the sleep disorders or other conditions disclosed herein. In some embodiments the compound is administered as a combination therapy whereas it is administered as a monotherapy in other embodiments.

Typically, the compound is administered as a monotherapy.

One skilled in the art will appreciate that a therapy administered in combination with the compounds of the present invention is directed to the same or a different disorder target as that being targeted by the compounds of the present invention. Administration of the compound of the invention is first, followed by the other therapy; or alternatively, administration of the other therapy may be first. The other therapy is any known in the art to treat, prevent, or reduce the symptoms of the targeted disorder, e.g., a sleep disorder, or other disorders, e.g., other CNS disorders. In addition, some embodiments of the present invention have compounds administered in combination with other known therapies for the target disorder. Furthermore, the other therapy includes any agent of benefit to the patient when administered in combination with the disclosed compound.

For example, in some embodiments where the other therapy is a drug, it is administered as a separate formulation or in the same formulation as the compound of the invention. A compound of the invention is administered in combination therapy with any one or more of commercially-available, over-the-counter or prescription medications, including, but not limited to antihistamines, antimicrobial agents, fungistatic agents, germicidal agents, hormones, antipyretic agents, antidiabetic agents, bronchodilators, antidiarrheal agents, antiarrhythmic agents, coronary dilation agents, glycosides, spasmolytics, antihypertensive agents, antidepressants, antianxiety agents, antipsychotic agents, other psychotherapeutic agents, steroids, corticosteroids, analgesics, cold medications, vitamins, sedatives, hypnotics, contraceptives, nonsteroidal anti-inflammatory drugs, blood glucose lowering agents, cholesterol lowering agents, anticonvulsant agents, other antiepileptic agents, immunomodulators, anticholinergics, sympatholytics, sympathomimetics, vasodilatory agents, anticoagulants, antiarrhythmics, prostaglandins having various pharmacologic activities, diuretics, sleep aids, antihistaminic agents, antineoplastic agents, oncolytic agents, antiandrogens, antimalarial agents, antileprosy agents, and various other types of drugs. For example, GABA agonists, alpha-2-delta modulators; 5-HT2a antagonists and inverse agonists are useful in combination with the compounds of the invention for treating sleep disorders. See Goodman and Gilman's The Basis of Therapeutics (Eighth Edition, Pergamon Press, Inc., USA, 1990) and The Merck Index (Eleventh Edition, Merck & Co., Inc., USA, 1989).

Examples of drugs used in combination with the compounds of the invention include, but are not limited to, AMBIEN® STILNOX® (zolpidem tartrate), indiplon, ESTORRA™ (eszopiclone), NEURONTIN® (gabapentin), LYRICA® (pregabalin), eplivanserin, SONATA® (zaleplon), ESTORRA™ (eszopiclone), ZOPICLONE™ (imovane), DESYREL™ (trazodone hydrochloride), SEROQUEL® (quetiapine fumarate), CLOZARIL® (clozapine), ZYPREXA™ (olanzapine), RISPERDAL® (risperidone), and M100907.

In one embodiment, the compounds of the invention are useful in combination with a mechanical therapy, such as CPAP. “CPAP” or “continuous positive airway pressure” is a mechanical treatment for sleep apnea and other sleep-related breathing disorders (including snoring) which is typically administered via the nose or mouth of the patient.

Under CPAP treatment, an individual wears a tight-fitting plastic mask over the nose when sleeping. The mask is attached to a compressor, which forces air into the nose creating a positive pressure within the patient's airways. The principle of the method is that pressurizing the airways provides a mechanical “splinting” action, which prevents airway collapse and therefore, obstructive sleep apnea. Although an effective therapeutic response is observed in most patients who undergo CPAP treatment, many patients cannot tolerate the apparatus or pressure and refuse treatment. Moreover, recent covert monitoring studies demonstrated that long-term compliance with CPAP treatment is very poor. It is known that patients remove their mask while sleeping.

In one aspect, the compound of the invention is administered in conjunction with a CPAP device to promote sleep. In another aspect, the compound of the invention is administered in conjunction with a CPAP device to improve sleep. In another aspect, the compound of the invention is administered in conjunction with a CPAP device to improve compliance regarding with CPAP treatment. Without wishing to be bound by theory, it is thought that by administering an effective amount of a sleep promoting compound of the invention to a patient in conjunction with CPAP treatment, the patient will sleep better and more soundly and therefore, not be as likely to remove the mask.

In one embodiment, the compound of the present invention is administered prior to the CPAP treatment. In another embodiment, the compound of the present invention is administered at substantially the same time as the CPAP treatment. In one embodiment, parallel administration of an effective amount of the compound is accomplished by adding an additional aerosol channel to the air pressure treatment portion of the CPAP device, thus administering the compound of the present invention in a nebulized form via the nasal or oral mask of the CPAP device. Alternatively, an effective amount of the compound can be added to the water or into the liquid reservoir that is typically part of the CPAP treatment device.

Using the CPAP mask treatment, the compound of the invention is administered in a low concentration throughout the night, or at higher concentrations, as a bolus, at different time points in the beginning and during the course of the night.

All publications and patent documents cited herein are incorporated herein by reference as if each such publication or document was specifically and individually indicated to be incorporated herein by reference. Citation of publications and patent documents is not intended as an admission that any is pertinent prior art, nor does it constitute any admission as to the contents or date of the same. The invention having now been described by way of written description, those of skill in the art will recognize that the invention can be practiced in a variety of embodiments and that the foregoing description and examples below are for purposes of illustration and not limitation of the claims that follow.

EXAMPLE 1 Synthesis of Doxepin Analogs

The compounds of the invention, and related derivatives, can be synthesized by methods known to one skilled in the art. Detailed methods for synthesizing these compounds are described below. See, also, PCT Publication No. WO 03/032912.

Step 1:

A mixture of THF (150 mL) and N,N,N′,N′-tetramethylethylenediamine (27.8 mL, 0.1853 mol, 2.5 eq.) was cooled to −78° C. s-Butyllithium (0.2 mol) was added slowly (40 min) maintaining the temperature between −65 to −78° C. After an additional 20 min stirring, 4-chlorobenzoic acid (11.60 g, 0.0741 mol, 1.0 eq.) dissolved in THF (150 mL) was added over a period of 60 minutes while maintaining the temperature between −65 to −78° C. After 2 h, iodomethane added, and stirring continued for 1 hour, at which time the cooling bath was removed. Water (164 mL) was added slowly and the reaction mixture was allowed to warm to room temperature. The layers were then separated, and the aqueous layer was washed with tert-butyl methyl ether (3×100 mL), and acidified with HCl to pH 1–2. The product was subsequently collected by filtration, washed with water, and dried under vacuum at 60° C. to give compound B (10.63 g, 84.0%). ¹H NMR was consistent with the structure.

Step 2:

Compound B (10.62 g, 62.3 mmol, 1.0 eq.) was dissolved in methanol (200 mL) and thionyl chloride (11.3 mL, 155.25 mmol, 2.5 eq.) was added slowly. The reaction solution was refluxed for 5 h, the solvent was removed, and the oil was taken up in methylene chloride (200 mL). The organic layer was washed with H₂O (3×100 mL), dried over MgSO₄, filtered, concentrated, and dried to give compound C (10.86 g, 94.4%). The structure was confirmed by ¹H-NMR.

Step 3:

Compound C (10.86 g, 58.8 mmol, 1.0 eq.) was dissolved in carbon tetrachloride (100 mL), and N-bromosuccinimide (15.7 g, 88.2 mmol., 1.5 eq.) was added followed by benzoylperoxide (0.05 g). The mixture was refluxed overnight. The reaction mixture was then filtered, and the solids were washed with dichloromethane. The combined organic filtrate was concentrated and dried to give compound D (7.1 g, 45.8%). The structure was confirmed by ¹H NMR.

Step 4:

Phenol (2.79 g, 29.63 mmol, 1.1 eq.) was dissolved in 2-butanone (75.0 mL) and potassium carbonate (11.17 g, 80.82 mmol., 3.0 eq.) was added, followed by compound D (7.1 g, 26.94 mmol., 1.0 eq.) dissolved in 2-butanone (75.0 mL). A catalytic amount of potassium iodide (0.05 g) was added and the mixture was refluxed overnight. The cooled reaction mixture was filtered and the solids were washed with 2-butanone. The combined filtrate was taken up in ethyl acetate (75 mL) and was washed with 5% aqueous NaOH (2×50 mL), brine (40 mL), and water (50 mL). The organic phase was concentrated and purified on silica gel to give compound E (9.32 g). The structure confirmed product by ¹H NMR.

Step 5:

A solution of NaOH (4.0g, 3.0 eq.) in H₂O (20 mL) was added to compound E (9.32 g, 1.0 eq.) dissolved in MeOH (50 mL), and refluxed for 45 min. After cooling, the solvent was removed, H₂O added (100 mL), and aqueous layer (aq. Extract-1) washed with ethyl acetate. The product was extracted into the ethyl acetate layer. The organic phase was then washed with water/5% NaOH (3×75 mL) (aq. Extract-2). Each of the aqueous extracts 1 and 2 (which were not combined) was acidified to pH 1–2 with HCl. The white precipitate obtained was taken up in dichloromethane (3×75 mL). After removal of the solvent and drying, aq. Extract-1 gave 1.61 g solid containing some product but mostly compound 1, and aq. Extract-2 gave 5.68 g product (compound F). The structures were confirmed by ¹H NMR.

Step 6:

Compound F (6.0 g, 22.84 mmol., 1.0 eq.) was dissolved in dichloromethane (75.0 mL) and trifluoroacetic anhydride (7.2 g, 34.26 mmol., 1.5 eq.) was added, followed by a catalytic amount of borontrifluoride etherate (0.4 mL). The reaction mixture was heated to 40° C. for 4 h. The reaction mixture was washed with water (50 mL), saturated NaHCO₃ (2×50 mL), and water (50 mL). The organic phase was dried over MgSO₄, filtered and concentrated. The crude product was purified on 120 g RediSep column using gradient elution, heptane/ethylacetate to give compound G (3.69 g, 66.0%). The structure was confirmed by ¹H NMR and LC/MS.

Step 7:

The ketone G, was subjected to McMurray reaction. Accordingly, titanium chloride (4.05 mL, 36.85 mmol.) was slowly added to a mixture of zinc dust (5.31 g, 81.2 mmol., 5.4 eq.) in anhydrous THF (60 mL) at 0° C. The mixture was then refluxed for 2.5 hours. N-carbethoxy-4-piperidone, (5.5 mL, 36.3 mmol., 2.4 eq.) and ketone G (3.69 g, 15.12 mmol., 1.0 eq.) were dissolved in anhydrous THF (40.0 mL) and added to the titanium (0) mixture, and the reaction mixture was refluxed for 6 h. An aq. solution of K₂CO₃ (150 mL of 10% aqueous solution) was then added and stirred for 30 min. The mixture was subsequently filtered over pad of celite, and the solids were washed with ethylacetate. The layers were separated and the organic phase was collected, dried over MgSO₄, and concentrated to give the compound H (8.15 g, 80.0% pure by HPLC). The structure was confirmed by ¹H NMR and LC/MS.

Step 8:

Compound H was dissolved in ethanol (60.0 mL), and an aq. solution of sodium hydroxide (10.2 g, 254.76 mmol., 12.0 eq.) in H₂O (15.0 mL) was added and refluxed overnight. The solids were filtered off, and then washed with ethanol. The filtrate was concentrated and the oily residue was taken up in dichloromethane (155 mL) and H₂O (40 mL). The aqueous layer was extracted with CH₂Cl₂ (3×50 mL) and combined with the organic layer. The combined organic phase was washed with brine, dried over NaSO₄, filtered and concentrated to give 3.95 g of crude compound I. The structure of compound I was confirmed by H NMR and LC/MS and the crude material was taken to the next step without purification.

Step 9:

Compound I (2.0 g, 6.41 mmol., 1.0 eq.), K₂CO₃ (1.77 g, 12.82 mmol., 2.0 eq.), halide (5.28 g, 32.05 mmol., 5.0 eq.) and DMF (25.0 mL) were combined and heated to 100° C. overnight. The crude reaction mixture was mixed with H₂O (30 mL) and CH₂Cl₂ (35 mL). The organic phase was separated and the aqueous phase was washed with CH₂Cl₂ (2×25 mL). The combined organic phase was washed with brine and concentrated. The crude material was purified on a silica column to give compound J (1.2 g). The structure was confirmed by ¹H NMR and LC/MS.

Step 10:

Compound I (2.0 g, 6.41 mmol, 1.0 eq.), aldehyde (1.7 g, 13 mmol, 2.0 eq.) and CH₂Cl₂ (20 mL) were taken in a flask under nitrogen and cooled to 0° C. Na(OAc)₃BH (2.6 g, 12.32 mmol, 1.9 eq.) was added in controlled aliquots and stirred at 0° C. for 30 min. the reaction mixture was allowed to reach room temperature and stirred overnight. The mixture was then diluted with CH₂Cl₂ (40 mL), an aq. solution of saturated NaHCO₃ (30 mL) was subsequently added, and the reaction mixture was stirred for 10 min. The organic phase was separated and the aq. phase was extracted with CH₂Cl₂ (2×25 mL). The combined organic layer was dried (NaSO₄), concentrated, and the crude material was purified on a silica column to give compound K (1.72 g). The structure was confirmed by ¹H NMR and LC/MS.

Step 11:

Compound K (1.6 g, 3.76 mmol, 1 eq.) was dissolved in ethanol (40.0 mL). An aqueous solution of sodium hydroxide (2.0 g, 50 mmol., 13.0 eq.) in H₂O (9.0 mL) was added and refluxed overnight. The solids were filtered off, and the solvents were then distilled off. The residue was taken up in H₂O (40 mL) and acidified with HCl to pH 1 and stirred for 20 min. The resulting solids were filtered, washed with heptane, and dried under high vacuum to give the compound 51a (1.59 g). The structure of the compound 51a was confirmed by ¹HNMR, LC/MS and elemental analysis.

Schemes 1 through 15, shown below, depict the synthesis of several doxepin-like compounds of the invention, with various degrees of substitution.

Table 7 shows analytical data for the sleep-inducing agents shown in Table 1.

TABLE 7 Analytical Data for Certain Disclosed Sleep-Inducing Agents Compound 47a Molecular Formula C25H29CIFNO4*0.1NaCl Molecular Weight 467.80 (HCl salt) Mass spec 426.2 (M + 1) Elemental Analysis (adjusted to account for 0.1 mol % of NaCl) Element Calculated Observed C 64.19 64.03 64.12 H 6.25 6.15 6.25 N 2.99 2.96 2.95 Compound 49b Molecular Formula C24H25ClFNO3 (HCl salt) Molecular Weight 429.92 (HCl salt) Mass spec 394.3 (M + 1 of free base) Elemental Analysis Element Calculated Observed C 67.05 66.71 66.76 H 5.86 5.9 5.78 N 3.26 3.18 3.21 Cl 8.25 8.19 8.27 Compound 49a Molecular Formula C24H27ClFNO3*0.15H2O Molecular Weight 434.64 (HCl salt) Mass Spec 396.2 (M + 1 of free base) Elemental Analysis Elemen Calculated Observed C 66.32 65.96 66.05 H 6.33 6.26 6.33 N 3.22 3.25 3.15 Cl 8.16 8.51 8.46 Compound 49c Molecular Formula C26H31ClFNO3*(o.75H2O) (.01 TBME) Molecular Weight 474.38 Mass spec 424.2 (M + 1 of free base) Elemental Analysis (adjusted to account for H2O, t-butyl methyl ether (TBME) Element Calculated Observed C 65.96 66.01 65.86 H 6.93 6.67 6.56 N 2.95 3.01 2.91 Cl 7.47 7.32 7.43 Compound 50b Molecular Formula C25H28NclO4*0.4H2O, 0.2HCl Molecular Weight 456.455 Mass spec 406.2 (M + 1 of free base) Elemental Analysis (adjusted to account for HCl, H2O) Element Calculated Observed C 65.78 65.85 65.89 H 6.4 6.25 6.18 N 3.07 3.00 3.06 Cl 9.32 9.21 9.15 Compound 50a Molecular Formula C25H30ClNO4*0.1H20 Molecular Weight 445.77 Mass spec 409.2 (M + 1) Elemental Analysis (adjusted to account for 0.1 mol % of H2O) Element Calculated Observed C 67.36 67.19 67.13 H 6.83 6.92 6.88 N 3.14 7.8 7.87 Cl 7.95 3.12 3.16

EXAMPLE 2 Sleep-Inducing Properties of Compounds of the Invention

Sleep in mammals can be divided into sleep occurring during periods of rapid eye movement (REM), accompanied by substantial brain activity, and periods of non-REM (NREM) sleep, accompanied by decreased brain activity. Typically, a normal nighttime sleep period is occupied primarily by NREM sleep, and thus NREM cumulation can serve as a measure of total sleep cumulation, e.g., significantly decreased NREM can be associated with insomnia and an accumulation of “sleep debt”, e.g., an accumulated physiological need for sleep that tends to persist until a sufficient amount of additional sleep is accumulated. Thus, an increase in NREM associated with a treatment can indicated the treatment's effectiveness in treating insomnia.

Sleep quality can be associated with sleep continuity or sleep maintenance. For example, a subject with sleep apnea wakes up numerous times during a sleep period, e.g., the subject has difficulty maintaining continuous sleep. Although such a subject can accumulate a typical nights length of sleep, e.g., 8 hours, the sleep is unrefreshing due to the waking caused by the sleep apnea. Thus, an increase in the longest uninterrupted sleep bout (LUSB, also known as longest sleep bout) associated with a treatment can indicate the treatment's effectiveness in enhancing sleep continuity, and therefore in treating sleep maintenance insomnia.

Sleep-wakefulness, locomotor activity and body temperature are monitored in male Wistar rats treated with a test compound (i.e., doxepin analog) initially at a concentration of 10 mg/kg. Higher and lower doses are assayed for select compounds (e.g., as high as 45 mg/kg, and as low as necessary to establish a no-effect dose). Treatments are administered at CT-18, the peak of the activity dominated period (6 hours after lights-off), and produced soporific (sleep-inducing) effects characterized by increased non-REM sleep time, increased sleep continuity, but without evidence of REM sleep inhibition or rebound insomnia.

Sleep-wakefulness, locomotor activity and body temperature were monitored in vivo with certain of the disclosed sleep-inducing agents 46a, 47a, 49a, 49b, 50a, 50b, and derivatives listed in Table 1. Adult, male Wistar rats (250 g at time of surgery, Charles River Laboratories, Wilmington Mass.) were anesthetized (2% isoflourane in medical grade oxygen) and surgically prepared with a cranial implant to permit chronic electro-encephalogram (EEG) and electromyogram (EMG) recording. Body temperature and locomotor activity were monitored via a miniature transmitter (Mini-Mitter, Bend, Oreg.) surgically placed in the abdomen. The cranial implant consisted of stainless steel screws (two frontal [+3.2 AP from bregma, ±2.0 ML] and two occipital [−6.9 AP, ±5.5 ML]) for EEG recording. Two Teflon®-coated stainless steel wires were positioned under the nuchal trapezoid muscles for EMG recording. All leads were soldered to a miniature connector prior to surgery, and gas sterilized in ethylene oxide. The implant assembly was affixed to the skull with dental acrylic. A minimum of three weeks was allowed for surgical recovery.

Each rat was permanently housed in its own individual recording cage located within separate, ventilated compartments of custom-designed stainless steel cabinets. Each cage was enhanced with a filter-top riser and low-torque swivel-commutator. Food and water were available ad libitum. A 24-hr light-dark cycle (12 hours light, 12 hours dark) was maintained throughout the study. Animals were undisturbed for at least 48 hours before and after treatments.

Sleep and wakefulness were determined using “SCORE-2000™” (Hypnion, Worcester, Mass.)—an internet-based sleep-wake and physiological monitoring system. The system monitored amplified EEG (bandpass 1–30 Hz), integrated EMG (bandpass 10–100 Hz), body temperature and non-specific locomotor activity (LMA) via telemetry, and drinking activity, continuously and simultaneously. Arousal states were classified on-line as non-REM (NREM) sleep, REM sleep, wake, or theta-dominated wake every 10 seconds. Total drinking and locomotor activity counts, and body temperature were quantitiated and recorded each minute, using EEG feature extraction and pattern-matching algorithms. From this data, the longest uninterrupted sleep bout (LUSB) was obtained. The classification algorithm used individually-taught EEG-arousal-state templates, plus EMG criteria to differentiate REM sleep from theta-dominated wakefulness, plus behavior-dependent contextual rules (e.g, if the animal was drinking, it is awake). Drinking and locomotor activity intensity (LMA) were recorded every 10 seconds, while body temperature was recorded each minute. Locomotor activity was detected by a telemetry receiver (Mini-Mitter) beneath the cage. Telemetry measures (LMA and body temperature) were not part of the scoring algorithm; thus, sleep-scoring and telemetry data were independent measures.

Compounds were administered at CT-18, the peak of the activity-dominated period, sufficient time was allowed to view the time course of the treatment effect before lights-on (6 hours post-treatment). Compounds were suspended in sterile 0.25% or 0.5% methylcellulose (1–2 ml/kg). Treatments were administered orally as a bolus.

A parallel group study design was employed. Vehicle controls were drawn from a large pool (N>200): a subset of the pooled vehicle controls was selected, based on computerized matching with the 24-hour pre-treatment baseline of the active treatment group.

The results of NREM and LUSB parameters were measured for the disclosed sleep-inducing agents 46a, 47a, 49a, 49b, 50a, 50b, and the derivatives in Table 1. Sleep inducing agents have greater values for NREM and LUSB at a given dose, particularly at low doses, and have increasing NREM and LUSB values with increasing dose.

TABLE 8 Sleep Inducing Properties* of Compounds # dose NREM LUSB # dose NREM LUSB # dose NREM LUSB 46a 3 12.1 5 48a 1 36.7 6.9 55b 10 7.7 2.5 10 36 8.2 3 50.8 11.2 55a 30 12.8 2 47a 1 5.5 2.9 10 58.6 10 56b 30 −9.9 −2.9 3 32.3 5.5 30 39.4 4.4 56a 30 6.4 4.3 10 41.1 16.7 53a 1 14.6 5 57a 30 −11 −5.3 30 56.9 10 3 38.6 17.2 66a 30 27.8 8.8 49b 3 22.5 10.4 10 51.5 14.4 58a 3 9.1 5.3 10 47.3 13.1 30 66.3 11.9 10 −12.5 7.6 30 43.2 15.9 61b 3 11.3 3.6 67b 10 12.6 4.6 49a 0.3 −6.6 2.8 10 34.8 14.6 30 21.1 10 1 18.8 4.3 30 57.4 9.7 51a 3 32.1 8.8 3 37.2 11.6 62a 10 23.2 7.4 10 60.3 18.2 10 45.3 14.1 30 25.2 9.1 30 49.3 6.3 30 49.1 12.9 61a 3 13.9 3.1 69a 3 32.2 7.1 50b 3 10.7 6.9 10 24 9.7 10 32.8 13.1 10 24.2 8.1 30 45.8 10.1 30 40 13.5 30 51.9 14.3 62b 30 10.3 2.5 70b 10 33.7 8.3 50a 3 12.7 4.8 30 32.6 12.9 30 43.2 13.8 10 32.6 9.3 70a 10 13.2 3.7 71a 30 8.1 3.6 30 41.9 11.2 30 33.6 6 68a 3 20.9 4.3 51b 3 34.7 8.4 45 29.3 12.1 10 45.9 7.8 10 45 8.3 69b 3 14.9 5.9 30 50.8 11.9 30 60.4 128 10 44.3 6.2 60a 10 −5.2 3.7 52a 3 13.6 8.2 15 43.4 14.4 67a 30 −11.5 6.5 10 26.8 5.7 20 39.4 11.6 59b 10 42.4 12.8 30 37.2 10.1 30 41.6 14 30 23.1 6.1 52b 10 7.5 2.9 54a 30 28.6 6.1 69e 3 21.2 5.6 30 26.8 7.1 64a 30 33.5 12.3 10 28.4 9.7 10a 1 −5 3.1 63a 30 9.6 4.6 20 54.6 12.3 3 −8.9 1.6 63b 10 −4.8 2.1 70e 3 25.7 6.6 10 15.1 4 65a 10 6.2 1.5 10 27.4 6.6 30 30.9 6.8 65b 10 −5.7 3.9 30 43.3 15 71e 30 34.5 4.1 *dose is in mg/kg; NREM and LUSB are in minutes.

EXAMPLE 3 Irwin Screen Side Effects

The Irwin screen can provide useful information on potential side effects of compounds on general physiological and behavioural functions. The screen was conducted by administering the test compounds orally in 0.25% aqueous methylcellulose using male Wistar rats, a frequently used species in such studies and for which background data are readily available.

The Irwin screen tests for numerous parameters in animals that have been administered the test compound. For example, the screen can include: in-cage effects, e.g., dispersion, respiratory rate, locomotor activity, restlessness, fighting, alertness, apathy, and exophthalmus; in-arena effects, e.g., transfer arousal, spatial locomotion, ptosis, startle, tail elevation, piloerection, touch escape, positional passivity, catalepsy, tighting reflex, visual placing, grip strength, pinna, corneal, pain response, and wire manoeuvre; parameters observed in handling, e.g., cyanosis, cutaneous blood flow, hypothermia, body tone, pupil size, light-pupil response, lacrimation, grooming, red staining, salivation, and provoked biting; general scores e.g., fearfulness, irritability, abnormal gait, abnormal body carriage, tremors, twitches, convulsions, bizarre behaviour, writhing, vocalisation, diarrhoea, number of defaecations, number of urinations, moribund, lethality, and abnormalities detected. Further details can be found in Irwin, S; Comprehensive observational assessment: I a. A systematic, quantitative procedure for assessing the behavioural and physiological state of the mouse. Psychopharmacologia (Berl.) 13:222–257, 1968, the entire teachings of which are incorporated herein by reference.

Irwin screening of the disclosed sleep-inducing agents was performed by Covance (Princeton, N.J.) according to Irwin, above; Covance Standard Operating Procedure (current revision of SOP PHARM 8.10); relevant regulatory authority guidelines ICH (International Committee for Harmonization) Guideline (Topic S7A; CPMP/ICH/539/00) on Safety Pharmacology Studies for human pharmaceuticals (November 2000); and all procedures carried out on live animals were subject to the provisions of United Kingdom Law, in particular the Animals (Scientific Procedures) Act, 1986. which obliges all UK laboratories to maintain a local ethical review process to ensure that all animal use in the establishment is carefully considered and justified; that proper account is taken of all possibilities for reduction, refinement or replacement and that high standards of accommodation and care are achieved.

All chemicals used were purchased from Colorcon, Ltd, Dartford Kent, UK unless otherwise noted and were of ACS reagent grade purity or higher. All test compound formulations were prepared on the day of dosing by Covance Harrogate Dispensary. The test compounds were formulated in 0.25% aqueous methylcellulose at the highest concentration required. Lower doses were obtained by serial dilution of the highest concentration using 0.25% aqueous methylcellulose. Dose levels are expressed in terms of the amount of test compound administered without regard to purity or active content. All formulations were stored at room temperature (nominally 10 to 30° C.) in sealed containers and protected from light.

An adequate number of male Wistar (Crl:WI(Glx/BRL/Han) BR:WH) rats were obtained from Charles River Ltd. (Margate, Kent, United Kingdom). The rats were approximately 5 weeks of age and weighed between 150 and 170 g on arrival. The animals were housed in groups of no more than six in polypropylene cages (33×15×13 cm) or (45×28×20 cm) with solid floors and Grade 10 woodflakes (Datesand Ltd., Cheshire, United Kingdom) as bedding. The cages were cleaned and dried before use. Aspen chew blocks were placed within the cages as a form of environmental enrichment. Routinely, holding rooms were maintained within acceptable limits for temperature and relative humidity (nominally 19 to 25° C. and 40% to 70%, respectively). These rooms were illuminated by fluorescent light for 12 hours out of each 24 hour cycle and designed to receive at least 15 fresh air changes per hour. Diet (RM1.(E).SQC. (Special Diets Services Ltd. Witham, United Kingdom) and water from the mains tap supply are provided ad libitum (except during handling). These were routinely analysed for specific constituents and were not found to contain any biological or chemical entity which might interfere with the test system. On arrival, all animals were examined for ill-health. Animals were acclimatised for a period of at least 5 days. During this time, animals were identified by their cage labels. A veterinary examination was performed before the start of any experimental procedures to ensure their suitability for the study. Prior to the start of the study, animals were allocated randomly to treatment groups and individually tail-marked as they come to hand. At the end of the study, the animals were euthanized.

Each animal received a single oral administration of vehicle or test article, using a constant dose of 1 mg/kg. Individual doses were based on individual body weights, obtained on the day of dosing.

The Irwin screen parameters above were systematically assessed in accordance with the relevant controls. In general, drug-induced changes, absent in normal animals, were scored using increasing integers with ‘0’ being normal (+/−, present/absent may also be used). Parameters present in normal animals were scored using an integer that allows for increases and decreases to be recorded. Detailed observations were performed at 30, 60, 90, 180 and 300 minutes post-dose. The animals were kept for a 7-day post-dose period during which time they will be observed daily for gross signs of toxicity and mortality.

The overall results of the Irwin screen are summarized in Table 9. It can be seen that many compounds of the present invention have a clean profile with regard to the Irwin screen.

TABLE 9 Side Effects in Irwin Screen Compound Irwin at          mg/kg dose 46a — 47a — 49b 10, 30 clean; 100 sleep effects through 10 h 49a 10 clean; 30, 100 sleep effects through 6 h 50b 10, 30 clean; 100 minor side effects 50a clean 51b 10, 30 clean; 100 sleep effects through 6 h 61b 10, 30 clean; 100 sleep effects through 24 h 61a 10, 30 clean; 100 side effects through 24 h 70a clean 69b clean 67c 10, 30 clean; 100 lethality 51a 10 clean; 30 some side effects; 100 lethality 69a 10, 30 clean; 100 significant side effects through 24 h 70b 10, 30 clean; 100 some side effects 59b clean 70e 10, 30 clean; 100 some side effects 71e 10, 30 clean; 100 many side effects

EXAMPLE 4 Disclosed Agents Have Reduced hERG Side Effects

The cardiac potassium channel, hERG, is responsible for the rapid delayed rectifier current (IKr) in human ventricles. This channel has been selected for evaluation because inhibition of IKr is the most common cause of undesirable cardiac action potential prolongation by non-cardiac drugs. Increased action potential duration causes prolongation of the QT interval that has been associated with a dangerous ventricular arrhythmia, torsade de pointes (Brown, A M; Rampe, D. (2000). Drug-induced long QT syndrome: is hERG the root of all evil?; and Pharmaceutical News 7, 15–20; Rampe, D; Roy, M L; Dennis, A; Brown, A M. (1997), the entire teachings of which are incorporated herein by reference). hERG channels were expressed in a human embryonic kidney (HEK293) cell line that lacks endogenous IKr. Expression in a mammalian cell line is preferable to transient expression in Xenopus oocytes because the latter shows a consistent 10–100 fold lower sensitivity to hERG channel blockers. See also, for example: A mechanism for the pro-arrhythmic effects of cisapride (Propulsid): high affinity blockade of the human cardiac potassium channel hERG. FEBS Lett. 417, 28–32; Weirich, J; Antoni, H. (1998); Rate-dependence of anti-arrhythmic and pro-arrhythmic properties of class I and class III anti-arrhythmic drugs. Basic Res Cardiol 93 Suppl 1, 125–132; and Yap, Y G; Camm, A J. (1999); and Arrhythmogenic mechanisms of non-sedating antihistamines. Clin. Exp. Allergy 29 Suppl 3, 174–181. The entire teachings of the preceding articles are incorporated herein by reference.

The in vitro effects of the disclosed sleep-inducing agents on the hERG (human ether-à-go-go-related gene) channel current (IKr, the rapidly activating, delayed rectifier cardiac potassium current) were determined by ChanTest (Cleveland, Ohio) according to Standard Operating Procedures of ChanTest.

All chemicals used were purchased from Sigma (St. Louis, Mo.) unless otherwise noted and were of ACS reagent grade purity or higher. Stock solutions of test articles and terfenadine (positive control) were prepared using dimethyl sulfoxide (DMSO) and stored frozen. Test article and positive control concentrations were prepared by diluting stock solutions into a HEPES (N-[2-hydroxyethyl]piperazine-N′-[2-ethanesulfonic acid])-buffered physiological saline (HB-PS) solution (composition in mM): NaCl, 137; KCl, 4.0; CaCl₂, 1.8; Mg Cl₂, 1; HEPES, 10; Glucose, 10; pH adjusted to 7.4 with NaOH (prepared weekly and refrigerated until use). Since previous results have shown that 0.3% DMSO does not affect channel current, all test and control solutions will contain 0.1% DMSO. If the final DMSO concentration must be greater than 0.3%, to reach a specified test article concentration, a separate vehicle control test with an n>2 was performed at the highest final DMSO concentration. Test and control solutions were prepared from stock solutions on a daily basis.

Cells used were human embryonic epithelial kidney cells (HEK293; source strain, American Type Culture Collection, Manassas, Va.; sub-strain, ChanTest, Cleveland, Ohio), transformed with adenovirus 5 DNA and transfected with hERG cDNA. Stable transfectants were selected by coexpression with the G418-resistance gene incorporated into the expression plasmid. Selection pressure was maintained by including G418 in the culture medium. Cells were cultured in Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12 (D-MEM/F-12) supplemented with 10% fetal bovine serum, 100 U/mL penicillin G sodium, 100 μg/mL streptomycin sulfate and 500 μg/mL G418.

Data acquisition and analyses were performed using the suite of pCLAMP programs (Axon Instruments, CA). Steady state was a limiting constant rate of change with time (linear time dependence) before and after test article application. The decrease in current amplitude upon reaching steady state was used to calculate the percent block relative to control.

All experiments were performed at room temperature (18° C.–24° C.). Each cell acted as its own control. One concentration (10 μM) of each test article was applied to cells expressing hERG (n≧3, where n=the number cells). Duration of exposure to each concentration was limited to the time necessary to reach steady-state block, but no longer than 10 minutes. One concentration of the positive control article (60 nM terfenadine) was applied to two cells (n≧2). Cells were transferred to the recording chamber and superfused with HB-PS solution. Pipette solution for whole cell recordings were (composition in mM): potassium aspartate, 130; Mg Cl₂, 5; EGTA (ethylene glycol tetraacetate), 5; ATP(adenosine triphosphate), 4; HEPES, 10; pH adjusted to 7.2 with KOH. Pipette solution was prepared in batches, aliquoted, stored frozen, and a fresh aliquot thawed each day. Patch pipettes were made from glass capillary tubing using a P-97 micropipette puller (Sutter Instruments, CA). A commercial patch clamp amplifier was used for whole cell recordings. Before digitization, current records were low-pass filtered at one-fifth of the sampling frequency.

Onset and steady state block of hERG current due to test article were measured using a pulse pattern with fixed amplitudes (depolarization: +20 mV for 2 s; repolarization: −50 mV for 2 s) repeated at 10 s intervals, from a holding potential of −80 mV. Peak tail current was measured during the 2 s step to −50 mV. A steady state was maintained for at least 30 seconds before applying test article or positive control. Peak tail currents were measured until a new steady state was achieved.

Table 10 shows the % blocking of the hERG channel at the indicated concentrations for various disclosed sleep inducing agents. Typically, values of about 10% or less are regarded as desirable, values from about 12% to about 30% can be acceptable if the compound has strong sleep-inducing performance and no other significant side effects; and values greater than about 30% are regarded as undesirable.

TABLE 10 hERG Blocking Compound hERG at      micromolar 47a   1% @ 10 49b  3.1% @ 10 49a  10.9 @ 10 49c 19.7% @ 10 50b 27.1% @ 10 50a  9.7% @ 10 51b   23% @ 10 61b 85.9% @ 10 62a 13.6% @ 10 61a 12.6% @ 10 70a  5.1% @ 1 69b 12.6% @ 10 51a 40.6% 69a  6.1% @ 1 70b 50.2% 68a 25.3% @ 10 59b   28% @ 10 69e −1.4% @ 1 70e  2.7% @ 1 71e  3.6% @ 1

EXAMPLE 5 Disclosed Agents Have Specificity for H1 Histamine Receptors

Binding assays were performed using the disclosed sleep-inducing agents 46a, 47a, 49a, 49b, 50a, 50b, and 49c, and derivatives selected from those listed in Table 1 in competitive binding assays with known standards for the H1 histamine receptor, and the M1, M2, and M3 muscarinic receptors.

The histamine H1 assays are described in Chang, et al. Heterogeneity of Histamine H₁-Receptors: Species Variation in [³H]Mepyramine Binding of Brain Membranes. Journal of Neurochemistry. 32:1653–1663 (1979); Martinez-Mir, M. I., Pollard, H., Moreau, J., et al. Three Histamine Receptors (H₁, H₂, and H₃) Visualized in the Brain of Human and Non-Human Primates. Brain Res. 526:322–327 (1990); Haaksma, E. E. J., Leurs, R. and Timmerman, H. Histamine Receptors: Subclasses and Specific Ligands. Pharmac. Ther. 47:73–104 (1990). The muscarinic assays are described in Buckley, N. J., Bonner, T. I., Buckley, C. M., and Brann, M. R. Antagonist Binding Properties of Five Cloned Muscarinic Receptors Expressed in CHO-K1 Cells. Mol. Pharmacol. 35:469–476 (1989). The assays were performed according to the preceding articles, with the following modifications. Chemical reagents in the following were obtained from Sigma, St. Louis, Mo.

For the histamine H1 assays, the receptors were obtained from bovine cerebellar membrane tissue, with a B_(max) (receptor number) of 6.2 femtomol/mg tissue (wet weight) and a KD (binding affinity) of 1.3 nM. A radioactive ligand ([³H]pyrilamine (15–25)Ci/mmol), K_(i) 1.9 nM, final concentration 2.0 nM) was employed, and 10 μM triprolidine (K_(i) 3.3 nM) was employed as a non-specific determinant, reference compound, and positive control. The receptor and the radioactive ligand were combined with the test compound at a range of test compound concentrations from about 10⁻¹⁰ to about 10⁻⁶ M, and the mixture was incubated out in 50 mM Na-KPO₄ (pH 7.5) at 25° C. for 60 minutes. The reaction was terminated by rapid vacuum filtration onto glass fiber filters. Radioactivity from the displaced radioactive ligand trapped onto the filters was determined and compared to control values in order to measure any interactions of the test compound with the histamine H1 binding site.

For the muscarinic assays, the receptors were obtained from human recombinant receptors expressed in CHO cells (PerkinElmer, Inc., Wellesley, Mass.). The radioactive ligand employed was [³H]-scopolamine, N-methyl chloride (80–100 Ci/mmol). (−)-Methylscopolamine bromide, 1.0 μM, was employed as the non-specific determinant, reference compound, and positive control. After incubation, reactions were terminated by rapid vacuum filtration onto glass fiber filters. Radioactivity from the displaced radioactive ligand trapped onto the filters was determined and compared to control values in order to measure any interactions of the test compound with the respective receptor.

For the M1 receptor assay, the B_(max) (receptor number) was 4.2 picomol/mg protein, and the K_(D) (binding affinity) of the receptor was 0.05 nM. The radioactive ligand was employed at a final concentration 0.5 nM, while the (−)-methylscopolamine bromide had a K_(i) of 0.09 nM. The receptor and the radioactive ligand were combined with the test compound at a range of test compound concentrations from about 10⁻¹² to about 10⁻⁵ M, incubated in Dulbecco's Phosphate Buffered Saline (PBS) for 60 minutes at 25° C., and worked up as described above.

For the M2 receptor assay, the B_(max) (receptor number) was 2.1 picomol/mg protein, and the K_(D) (binding affinity) of the receptor was 0.29 nM. The radioactive ligand was employed at a final concentration 0.5 nM, while the (−)-methylscopolamine bromide had a K_(i) of 0.3 nM. The receptor and the radioactive ligand were combined with the test compound at a range of test compound concentrations from about 10⁻¹² to about 10⁻⁵ M, incubated in Dulbecco's Phosphate Buffered Saline (PBS) for 60 minutes at 25° C., and worked up as described above.

For the M3 receptor assay, the B_(max) (receptor number) was 4.0 picomol/mg protein, and the K_(D) (binding affinity) of the receptor was 0.14 nM. The radioactive ligand was employed at a final concentration 0.2 nM, while the (−)-methylscopolamine bromide had a K_(i) of 0.3 nM. The receptor and the radioactive ligand were combined with the test compound at a range of test compound concentrations from about 10⁻¹² to about 10⁻⁵ M, incubated in 50 mM TRIS-HCl (pH 7.4) containing 10 mM MgCl₂, 1 mM EDTA for 60 minutes at 25° C., and worked up as described above.

Adenosine, purinergic A₁ binding assay was performed according to published procedures. See, e.g., Bruns, et al., Naunyn Schmiedebergs Arch. Pharmacol., 335(1): 59–63 (1987), with minor modifications; and Ferlany, et al. Drug Dev. Res. 9:85–93 (1986).

Adenosine, purinergic A₂ binding assay was performed according to published procedures. See, e.g., Jarvis, et al., J. Pharmacol. Exper. Ther. 251(3): 888–93 (1989) with modifications; and Bruns, et al., Mol. Pharmacol. 29(4): 331–46 (1986) with modifications.

Dopamine, D₁ (human recombinant) binding assay was performed according to published procedures. See, e.g., Jarvie, et al. J. Recept Res., 13(1–4): 573–90 (1993); and Billard, et al. Life Sciences, 35(18): 1885–93 (1984), with modifications

Dopamine, D₁ (human recombinant) binding assay was performed according to published procedures. See, e.g., Jarvie, et al. J. Recept Res., 13(1–4): 573–90 (1993); and Gundlach, et al. Life Sciences, 35(19): 1981–8 (1984) with modifications

Binding to H1 can be an indication of the desired sleep-inducing activity of the compound. Binding to muscarinic receptors shows non-specific binding, and can indicate anti-cholinergic activity which can result in undesired side effects, e.g., the side effects of many known antihistamines, e.g., blurred vision, dry mouth, constipation, urinary problems, dizziness, anxiety, and the like. A decrease in the binding of the compounds to the M1–M3 receptors, relative the binding of the compound to the H1 receptor, is an indication of the greater specificity of the compound for the histamine receptor over the muscarinic receptor. Moreover, a drug with increased specificity for the histamine receptor would possess less anti-cholinergic side effects. Table 11 shows the inhibition constant K_(i) in nM for H1 and the muscarinic receptors. It can be seen that the disclosed compounds are highly specific for H1 over the muscarinic receptors. Thus, the disclosed compounds can be expected to exhibit good sleep-inducing performance with limited side effects associated with muscarinic receptor inhibition.

TABLE 11 Disclosed Agents Have Specificity for H1 Histamine Receptors Ki, nanomolar Compound H1 M1 M2 M3 46a 134  >10K 2450 >10K 47a 111  >10K >10K >10K 49b 61.4  >10K >10K >10K 49a 69.5  >10K >10K >10K 49c 29.9  >10K >10K >10K 50b 69.8  >10K >10K >10K 50a 27.2  >10K >10K >10K 51b 72  >10K >10K >10K 61b 12.2  569 3090 >10K 62a 128  >10K >10K >10K 61a 182  >10K >10K >10K 62b 56.5  >10K >10K >10K 70a 47.9  >10K 3310 >10K 69b 54.9  >10K >10K >10K 67b 62.5  >10K >10K >10K 51a 26.4  >10K >10K >10K 69a 109  >10K >10K >10K 70a 36.8  811 1360 >10K 59b 66.7  >10K >10K >10K 70e 136  >10K >10K >10K 71e 60.7 12100 5130 >10K

Evaluation of Compounds

The following pharmacokinetic parameters are computed from the individual plasma concentrations of the modified antihistamine compound using a noncompartmental approach and appropriate validated pharmacokinetic software (e.g., WinNonlin Professional). Concentration values reported as BLQ are set to zero. If concentration data are available, interim calculations are done (non-QC.d data) between periods if possible. Dose escalation does not depend on pharmacokinetic calculations.

Descriptive statistics, including mean, standard deviation, coefficient of variation, geometric mean, median, minimum and maximum are computed for each pharmacokinetic parameter by dose group. Descriptive statistics for natural-log transformed AUC(0-t), AUC(0-inf), and Cmax are provided for each dose level. In addition, mean and median concentration versus time graphs are provided.

Dose proportionality following study medication is explored by analyzing natural log-transformed pharmacokinetic variables AUC(0-t), AUC(0-inf), and Cmax with a linear model including the natural log-transformed dose as covariates. Dose proportionality is concluded if the 95% confidence interval for the slope of the covariate includes the value of 1. Dose linearity for AUC(0-t), AUC(0-inf), and Cmax is also explored by a linear model. See, e.g., Gibaldi and Perrier, Pharmacokinetics, Second Ed., Marcel Dekker: New York, N.Y. (1982). Nominal sample collection times were used in calculations, except where actual sampling times fell outside the protocol-specified acceptable time ranges. The following parameters were estimated:

-   C_(max) Maximum plasma concentration. -   T_(max) Time to maximum concentration. -   C_(max) and T_(max) were reported directly from the     concentration-time data. -   AUC_(0-T) Area under the plasma concentration-time curve from time 9     to the last time point with measurable concentrations, estimated     bylinear trapezoidal rule. -   AUC₀₋₀₀ Area under the plasma concentration-time curve extrapolated     to infinity, calculated using the formula:     AUC ₀₋₀₀=AUC₀₋₁+C₀/λ₀ -    Where C_(t) is the last measurable concentration in plasma and     λ_(z) is the terminal phase elimination rate constant estimated     using log-linear regression during the terminal elimination phase.     The number of points used in λ_(z) calculation was determined by     visual inspection of the data describing the terminal phase. At lest     the last three time points with measurable values were used in λ_(z)     calculation. The number of points used in λ_(z) calculation is based     on the best correlation (r₂ adjusted) obtained for the time points     describing the terminal elimination phase. A r₂ adjusted value for     the regression line is considered to accurately define the terminal     elimination phase if the value is >0.7. -   T_(1/2) Elimination half-life, determined by In(2)λ_(z). -   CL Systemic clearance; for intravenous bolus or infusion, calculated     using the formula:     CL=Dose/AUC ₀₋₀₀ -    Report CL/F, where F=Absolute bioavailability, for all other routes     of administration. -   V₂ Volume of distribution for all routes of administration,     calculated using the formula:     V _(z) =CLλ _(z) -    CL/F is used to calculate V₂/F for extravascular routes of     administration.

Pharmacokinetic analysis is performed using WinNonlin Professional Edition (Pharsight Corporation, Version 3.3 or 4.1). Descriptive statistics such as mean and standard deviation are calculated in Microsoft Excel (Version 8.0e).

Metabolism of test articles in monkey and human cryopreserved hepatocytes is assayed as follows:

MATERIALS Manufacturer, lot number and exp. Materials Date Hepatocytes from Monkey Cellzdirect Human Williams E medium Sigma W1878, exp 2004-11 Foetal calf serum Fisher BW 14-501F, lot 01104637, exp 17 Feb 10 0.45 Trypan Blue Biowhittaker 17-942E, lot 01104637, exp Jan 14 Test Material Stock CB-1/III/6 Solution DMSO Fisher BP23 1-100, lot 041215, exp 12 Jul 09 10 mM ethoxycoumarin PSLB 22-A-15, exp Sep. 25, 2004 in methanol ACN Fisher A998-4, lot 041181, exp June 2007 Formic Acid Fisher 032879, exp Mar. 14, 2006 Pre-Incubation Preparation:

Sample is diluted with DMSO, to prepare 100 μM and 10 μM stocks. 0.1% formic acid in acetonitrile is prepared by the addition of 1 mL formic acid per 1 L acetonitrile (store RT for 3 months). 10 minute, 60 and 120 minute 96 well quenching plates are prepared with 150 μL acetonitrile+0.1% formic acid in each well. Store on ice or refrigerated.

Next, hepatocytes are thawed and 100 μL of cell suspension is placed into a microfuge tube with 100 μL 0.4% Trypan Blue solution and gently mix by inversion. A small amount of the stained cell suspension (approximately 15 μL) is placed into a clean hemacytometer with a coverslip. The hemacytometer is placed onto the stage of the microscope and the focus and power are adjusted until a single counting square fills the field. The number of cells in the four outside corner subdivided squares of the hemacytometer are counted. Viable cells are opalescent, round, and pale with a darker outline. Non-viable cells are dark, opaque blue.

The % viability is calculated as the number of viable cells divided by the total of cells X 100.

The viable cell density and total number of viable cells are calculated: Viable cell Density (D)=Mean 3 of viable cells counted (C)×10^(4×f2); Total number of viable cells (E)=D×26 (resuspension volume). The additional media required to achieve a concentration of 1×10⁶ cells/mL is calculated: Volume of additional medium=total viable cells/1×10⁶ (E)−26 mL

Cells are diluted accordingly and stored at room temperature.

Incubations

198 μL of hepatocytes are transferred to relevant wells on dosing plate. The remaining hepatocyte suspension is combined and place in a suitable container of near boiling water and left for 5 minutes to inactivate the cells (for inactive controls and standard curve preparation).

198 μL of inactive hepatocytes are transferred to control wells and 198 μL of blank media are transferred to buffer control wells. Plates are preincubated for at least 15 min. Reactions are started 2 μL of appropriate test compound dilution from dosing plate. Plates are incubated in an incubator set at 37° C. for approximately 10 minutes, then 50 μL of incubate is removed to 10 a minute quenching plate containing 150 μL acetonitrile+0.1% formic acid and stored refrigerated or on ice. Following 60 minutes, 50 μL of incubate is removed to 60 minute quenchnig plate containing 150 mL acetonitrile+0.1% formic acid and stored refrigerated or on ice. Following 120 minutes, 50 mL of incubate is removed to 120 minute quenching plate containing 150 μL acetonitrile+0.1% formic acid and stored refrigerated or on ice. The remaining 50 μL is frozen in incubation plates. Tubes are then centrifuged at ˜4° C. at ˜1400×g for ˜10 minutes. 100 μL of supernatant is diluted with 100 μL water in analysis plates, plates are stored frozen at −20° C. prior to analysis.

Preparation of Standard Curves

0.1 μM standard is prepared by the addition of 2 μL of 10 μM dosing solutions to 198 μL of inactive hepatocytes in standard prep plate. 150 μL acetonitrile+0.1% formic acid is added to the standard quenching plate. 150 μL of 0.1 μM standard is transferred into one column of a standard plate. 75 μL inactive hepatocytes is added to remaining wells. 75 μL from 0.1 μM standard is transferred into adjacent well in column in the plate, and mixed well by titration. Serial dilution is continued. 75 μL is removed from final standard (all wells contain 75 μL). Plates are incubated at approximately 37° C. for 10 minutes. 50 μL is transferred into standard quench plate containing 150 mL acetonitrile+0.1% formic acid. Plates are centrifuged along with samples and dilute supernatant 1:1 with water as above. Samples are stored frozen at ˜−20° C.

EXAMPLE 6 Clinical Evaluation of Doxepin Analogs

The goal of a human clinical trial is to collect data on the effects of modified antihistamines. Such data includes, for example, clinical signs and symptoms from physical exam, adverse events, laboratory safety (e.g., hematology, serum clinical chemistry, urinalysis), vital signs (e.g., blood pressure, heart rate, temperature, respiratory rate), and electrocardiogram (ECG) data.

The clinical trials are conducted as follows:

I. Subject Selection

A minimum of 18 subjects are used (2 enrollment groups of 9 subjects each). Subject candidates fulfilling the following inclusion criteria are eligible for participation in the study:

-   -   Healthy adult male subjects, 18–45 years of age.     -   Weighing at least 60 kg and within 15% of their ideal weights         (see Table of Desirable Weights of Adults,. Metropolitan Life         Insurance Company, 1983).     -   Medically healthy subjects with clinically insignificant         screening results (e.g., laboratory profiles, medical histories,         ECGS, physical exam).

Subject candidates fulfilling one of the following exclusion criteria are ineligible for participation in the study:

-   -   History or presence of significant cardiovascular, pulmonary,         hepatic, renal, hematologic, gastrointestinal, endocrine,         immunologic, dermatologic, neurologic, or psychiatric disease.     -   History or presence of sleep disorders.     -   History of chronic or seasonal allergies requiring treatment         with H1 receptor antagonists (i.e., terfenadine, astemizole)         within the 90 days prior to the study.     -   History or presence of alcoholism or drug abuse within the past         2 years.     -   Tobacco or nicotine use within the 90 days prior to the study.     -   Known hypersensitivity or idiosyncratic reaction to the study         drug, possible excipients of the study formulation (Captisol®;         sodium saccharin, F.C.C.; glycerin, U.S.P.; orange flavor;         methylcellulose 400 centipoise, U.S.P.; opurified water), or         related compounds.     -   Donation (standard donation amount or more) of blood or blood         products within 90 days prior to the study.     -   Participation in another clinical trial within 90 days prior to         the first dose.     -   History or presence of any disease, medical condition, or         surgery, which may have an effect on drug absorption,         metabolism, distribution, or excretion.     -   Weight loss or gain (±10%) within 30 days prior to the study.     -   Regular consumption of (e.g., more days than not) excessive         quantities of caffeine-containing beverages (e.g., more than 5         cups of coffee or equivalent per day) within 30 days prior to         the study.     -   Any condition that, in the opinion of the Investigator or         Sponsor makes the subject unsuitable for the study.     -   Use of any prohibited prior or concomitant medications.

Each subject who completes the study screening assessments, meets all eligibility criteria, and is accepted for the study is assigned a unique identification number and receives designated doses of the modified antihistamine and placebo according to a randomization scheme. The randomization scheme is available only to the clinic pharmacy staff preparing the drug (who are not involved in the administration of the drug) and is not made available to the subjects, analysts, or members of the staff responsible for the monitoring and evaluation of the adverse experiences.

Subjects may be withdrawn from the study by the Principal Investigator for the following reasons:

-   -   Secondary occurrence of a major exclusion criteria.     -   To protect their health.     -   Adverse events.     -   Difficulties in blood collection.     -   To protect the integrity of the study.     -   Protocol violation.     -   Failure to comply with study directions.

The clinical report includes reasons for subject withdrawals as well as details relevant to withdrawal. Subjects withdrawn from the trial prior to study completion undergo all procedures scheduled for study completion. Subjects withdrawn due to any adverse event (whether serious or non-serious) or clinically significant abnormal laboratory test values are evaluated by the Investigator, or a monitoring physician, and are treated and/or followed up until the symptoms or values return to normal or acceptable levels, as judged by the Investigator.

II. Study Restrictions

Subjects do not take prescription or over-the-counter medication (including herbal products) during the 7 days preceding the study until the final sample of the final pharmacokinetic sampling period has been collected. Additionally, consumption of foods and beverages containing the following substances is prohibited as indicated:

-   -   Methylxanthine: 72 hours before each dosing and throughout the         period of sample collection, i.e., caffeine beverages and         equivalents (e.g., chocolate bars) are prohibited.     -   Alcohol: 72 hours before each dosing and throughout the period         of sample collection.

All medications taken during the 30 days prior to study start are recorded. Any medications taken for chronic or seasonal allergies in the 90 days prior to the study is recorded.

Pre-Study Subject Screening: The Informed Consent Form is administered at screening. Within 14 days prior to dosing, medical history and demographic data, including name, sex, age, race, body weight (kg), height (cm), alcohol use, and tobacco use are recorded. Each subject receives a physical examination including complete vital signs, 12-lead ECG, and laboratory tests as specified. The laboratory tests include the following:

-   -   a) Hematology including hemoglobin, MCV, red blood cell count,         hematocrit, MCHC, white blood cell count with differential         platelet count and MCH;     -   b) Serum Chemistry including bun, albumin, ALT (SGOT),         creatinine, alkaline phosphatase, glucose, total bilirubin,         creatine phosphokinase (CPK), sodium, uric acid, AST (SGOT) and         triglycerides;     -   c) Urinalysis including appearance and color, glucose, nitrite,         pH, ketones, urobilinogen, specific gravity, bilirubin,         leukocytes, protein and blood;     -   d) Additional Tests including HIV, urine drug screen, HbsAg,         cannabinoids, HCV, benzodiasepines, HCV, amphetamines, hepatitis         A (IgM), opiates, alcohol, cocaine, and continine.

Subject Management: Subjects are housed from at least 36 hours before dosing until completion of the 24-hour postdose events. They will return for a follow-up visit one week following the final dose or upon early withdrawal.

Subjects remain semi-recumbent in bed for the first 4 hours following drug administration. However, should adverse events occur at any time, subjects are placed in an appropriate position or are permitted to lie down on their right side. Subjects do not engage in strenuous activity at any time during the confinement period.

Standard meals are provided on Day 1 and Day 2. On Day 1, subjects are required to fast for a minimum of 10 hours overnight before dosing and for at least 4 hours thereafter. However, if the option for a previous dose in the fed state is used in Period 3 of Group 2, a standard high-fat meal is given 30 minutes prior to dose. In this case, the high-fat breakfast (i.e., approximately 50% of calories from fat) consists of two eggs fried in butter, two strips of bacon, two slices of buttered toast, four ounces of hash brown potatoes, and eight ounces of whole milk. Foods and beverages containing caffeine or equivalent (e.g., chocolate bars) are prohibited during confinement.

Water is not permitted from 2 hours before until 2 hours after dosing. Water is allowed at all other times. Standard meals are provided at approximately 4 and 9 hours after dosing, and at appropriate times thereafter.

III. Drug Administration

Subjects receive the dose for each period as assigned according to the randomization schedule for dosing sequence for each dose (enrollment) group. Subjects receive the assigned dose in a glass dosing cup, and within each dose group, all doses, active and placebo, are administered at the same volume to maintain the double-blind. Subjects are instructed to swallow the dose.

A total of 240 mL of water is given with dosing. A designated portion of the water (assigned by pharmacist based on dosing volume) is added to the emptied dosing cup, swirled to rinse, and swallowed by the subject. This process is repeated twice and then the remainder of the water is consumed by the subject.

The starting dose for the first human dose level is based on the toxicity and safety profiles in the preclinical studies. The equivalent body surface area conversion from human to rat is ⅙ (Toxicological Handbook, Michael J. Dereleko, CRC press, Boca Raton, Fla.). Based on NOAEL of 30 mg/kg/day for rat and body surface equivalent criteria, the equivalent dose in an individual of 60 kg is 300 mg/day (⅙×30 mg/kg/day [rat NOAEL]×60 kg). Based on NOAEL dose in rat (30 mg/kg/day), the dose of 3 mg is approximately 1/10 of the NOAEL dose in rats. The highest dose proposed of 160 mg is also below the NOAEL in rats.

If a dose limiting toxicity (Grade 3 or 4 according to the grade scale modified from the WHO Common Toxicity Criteria—Appendix I) deemed to be related to the study medication is observed in any 2 of the 6 subjects at any dose level, dose escalations are stopped, and the prior dose is considered the maximum tolerated dose (MTD).

If one subject at any dose level experiences a dose limiting toxicity, the Principal Investigator (in consultation with the Sponsor) decides, using good clinical judgment, whether to proceed to the next dose level as planned, or to adjust the next dose level downward from the dose planned. This consultation is done for all groups following the previous dose group to decide whether to proceed with planned doses or to adjust doses downward. Additionally, the planned doses may be substituted with intermediate doses if emerging safety or tolerability issues become apparent (i.e., there does not have to be a Grade 3 or 4 event) from the preceding dose that suggests the need to escalate more slowly.

Dose increments is only permitted if, in the opinion of the Principal Investigator, adequate safety and tolerability have been demonstrated at the previous lower dose. In all cases, the Principal Investigator uses good clinical judgment to decide whether to adjust the dose or to stop the study based on an assessment of all factors relevant to the safety of the subjects.

The Principal Investigator reviews check-in data (e.g., physical examination results, vital signs, questionnaire, and clinical laboratory results (e.g., serum chemistry, hematology, urinalysis, and urine drug screen) for clinically significant changes since screening or the previous period. The Principal Investigator determines if the subject will be dosed or withdrawn for the study based on this review.

IV. Clinical Observation

A hematology panel, a serum chemistry panel and a urinalysis is performed at screening, at each check-in, 24 hours following each dose, and one week following the final dose, or upon early withdrawal. Blood samples (approximately 7 mL) are collected from an indwelling intravenous catheter into evacuated glass tubes containing sodium heparin predose and at 0.25, 0.5, 0.75, 1.0, 1.5, 2, 3, 4, 6, 8, 10, 12, 18, and 24 hours postdose. Urine samples are collected predose and during the 0–8 hour interval each period. Samples collected during the interval are not pooled. Each void is considered a sample. The voiding times are at will, not scheduled (with the exception of the predose void and the void at the end of the 8 hour interval).

Vital signs are measured during the screenings. When the time of vital signs coincides with an ECG only, the vital signs are taken 10 minutes prior to the ECG. When the time of vital signs coincides with a blood draw or a blood draw and ECG, the vital signs are taken 10 minutes prior to the blood draw. Respirations and temperature is monitored at check-in, 24 hours following each dose, and one week following the final dose, or upon early withdrawal. Single measurements of blood pressure and heart rate are taken after a minimum of 5 minutes in a semi-recumbent position. Measurements taken during study confinement will be monitored with an AVS machine at check-in; 0 (predose); 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 18, and 24 hours postdose; and one week following the final dose, or upon early withdrawal. For any heart rate measurement greater than 100 beats per minute, the heart rate will be rechecked two minutes later. On Day 1, at approximately 24 hours prior to dosing, 3 measurements of blood pressure and heart rate, taken 2 minutes apart, are taken as described as described above.

A standard 12-lead ECG is performed for each subject at screening, on Day 1 at times coinciding with Day 1 times of 1 hours prior to dose and 1, 1.5, 2, 3, 4, and 6 hours postdose; on Day 1 at 1 hour predose and 1, 1.5, 2, 3, 4, 6, and 24 hours postdose; and one week following the final dose or upon early withdrawal. Additional ECGs may be performed at other times if deemed necessary. All standard 12-lead ECGs are recorded for 10 seconds. Timing and registration technique for ECGs is standardized for all subjects. Subjects should be lying down for at least 1 minute prior to each 12-lead ECG evaluation. The Principal Investigator evaluates PR, QRS, QT, and QTc intervals. When the time of ECGs coincides with a blood draw, the ECG will be taken following the draw.

A physician examines each subject at screening, each check-in, 24 hours following each dose, and one week following the final dose, or upon early withdrawal. Additional examinations are performed at other times if deemed necessary.

Immediately before vital signs measurements 1 hour predose and at 1, 2, 6, and 24 hours postdose (the vital signs are taken 10 minutes prior to the blood draw designated at these times), subjects are presented a visual analogue scale and asked to draw a vertical mark across a 100 mm line at the point ranging between Very Sleepy and Alert/Wide Awake, which best describes their level of alertness at that time.

The subjects are instructed to inform the study physician or staff of any adverse events or intercurrent illnesses experienced during the trial. Additionally, a specific inquiry regarding adverse events is conducted prior to dosing, at 2, 4, 8, and 24 hours postdose, and one week following the final dose, or upon early withdrawal. Questions are posed in a non-specific manner so as not to bias the response.

Any subject who has any adverse event (whether serious or non-serious) or clinically significant abnormal laboratory test values is evaluated by the Investigator, or a monitoring physician, and is treated and/or followed up until the symptoms or values return to normal or acceptable levels, as judged by the Investigator. A physician, either on-site or at a nearby hospital emergency room, administers treatment of any serious adverse events. Where appropriate, medical tests and examinations are performed to document resolution of event(s). Outcome is classified as, e.g., resolved, improved, unchanged, worse, fatal, or unknown (lost to follow-up).

V. Reporting

All adverse events occurring during the clinical trial are recorded. Adverse events are coded using MedDRA (version 4.1). An adverse event/experience (AE) is any unwarranted medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product that does not necessarily have a causal relationship with this treatment (ICH/WHO). An adverse event (AE) is, therefore, any unfavorable and unintended sign, (including, for example, an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medical product, whether or not considered related to the medical product (ICH/WHO).

The Investigator reviews each event and assesses its relationship to drug treatment (i.e., unrelated, unlikely, possibly, probably, almost certainly). Each sign or symptom reported is graded on a 3-point severity scale (mild, moderate, or severe) and the date and time of onset, time relationship to drug dosing, duration, and outcome of each event is noted. The following definitions for rating severity are used: (1) Mild: The adverse event is easily tolerated and does not interfere with daily activity; (2) Moderate: The adverse event interferes with daily activity, but the subject is still able to function; (3) Severe: The adverse event is incapacitating and requires medical intervention.

If any of the above adverse events are serious, special procedures are followed. All serious adverse events are reported to the Sponsor within 24 hours and followed by written reports within 48 hours, whether or not the serious events are deemed drug-related.

A Serious Adverse Event (SAE) is any untoward medical occurrence that, at any dose, results in death, is life-threatening, results in permanently disability or incapacitation, requires inpatient hospitalization, prolongs inpatient hospitalization, is a congenital anomaly, may jeopardize the subject or may require intervention to prevent one or more of the other outcomes listed above.

VI. Pharmacokinetics

The following pharmacokinetic parameters are computed from the individual plasma concentrations of the modified antihistamine compound using a noncompartmental approach and appropriate validated pharmacokinetic software (e.g., WinNonlin Professional). Concentration values reported as BLQ are set to zero. If concentration data are available, interim calculations are done (non-QC.d data) between periods if possible. Dose escalation does not depend on pharmacokinetic calculations.

Descriptive statistics, including mean, standard deviation, coefficient of variation, geometric mean, median, minimum and maximum are computed for each pharmacokinetic parameter by dose group. Descriptive statistics for natural-log transformed AUC(0-t), AUC(0-inf), and Cmax for HY2901 are provided for each dose level. In addition, mean and median concentration versus time graphs are provided.

Dose proportionality following study medication is explored by analyzing natural log-transformed pharmacokinetic variables AUC(0-t), AUC(0-inf), and Cmax with a linear model including the natural log-transformed dose as covariates. Dose proportionality is concluded if the 95% confidence interval for the slope of the covariate includes the value of 1. Dose linearity for AUC(0-t), AUC(0-inf), and Cmax is also explored by a linear model.

VII. Assessment of Safety

A by-subject treatment-emergent adverse event data listing including verbatim term, preferred term, treatment, severity, and relationship to treatment is provided.

The number of subjects experiencing adverse events and number of adverse events is summarized by dose level using frequency counts.

Safety data including laboratory evaluations and vital signs assessments is summarized by dose level and time point of collection. Descriptive statistics are calculated for quantitative safety data and frequency counts are compiled for classification of qualitative safety data. In addition, a mean change from baseline table is provided for vital signs and a shift table describing out of normal range shifts is provided for clinical laboratory results.

ECG results are classified as normal and abnormal and summarized using frequency counts by dose group and time point of collection. Descriptive statistics are calculated for PR, QRS, QT, and QTc intervals.

Changes in physical exams are described in the text of the final report.

Heart rate data are summarized by treatment group and time point using descriptive statistics, as will individual change from baseline values. Mean change from baseline results are used to compare active dose groups to placebo at each time point. Data from six completed subjects per dose level should provide 80% certainty to detect a difference of 20 beats per minute. An interim analysis is completed following each period.

VIII. Assessment of Efficacy

VAS sedation scores are summarized by time point of collection for each dose level using descriptive statistics.

EXAMPLE 7 Preclinical Evaluation of HY2901

Prior to human clinical testing of HY2901 (also referred to herein as Compound 49a), pre-clinical testing was performed. Pre-clinical evaluation of HY2901 included the following tests:

i. Preclinical Absorption, Distribution, Metabolism and Excretion

HY2901 was administered to rats, dogs, and cynomolgus monkeys at a dose of 3 mg/kg orally and intravenously. Plasma samples were collected from all species for pharmacokinetic analysis. HY2901 was rapidly and highly absorbed after oral administration in all species. The Tmax (in hours) was 0.25, 0.5, and 1.5 in the rat, dog, and monkey, respectively. The half-life (in hours) was 1.1, 4.2, and 4.4 in the rat, dog, and monkey, respectively. HY2901 is 75% protein bound in rat plasma and 60% protein bound in human plasma.

The brains were collected from rats after oral administration to determine brain levels of the parent drug. When brain and free drug levels in plasma were compared in the rat, it was evident that the free drug in plasma was in equilibrium with the brain (free drug to plasma ratio of 1). There was a clear correlation between plasma and brain levels in the rat over a wide range of plasma concentrations.

Unchanged HY2901, as well as metabolites, has been found in the urine of animal species administered HY2901.

Cytochrome P450 inhibition was studied with HY2901 in vitro. HY2901 did not inhibit the activity of CYP 1A2, 2C9, 2C19, 2D6, or 3A in a commercially available human microsomal preparation. In addition, the in vitro rate of metabolism in rat, dog, monkey, and human hepatocyte cultures was determined for HY2901. Although HY2901 was extensively metabolized by rat hepatocytes, little metabolism was observed in the human cultures.

ii. Cardiac Effects Focus

The primary toxicological issue studied during the clinical candidate selection phase of the project was QT interval prolongation. Historically, H1 antagonists have been associated with this effect. QT prolongation in rare instances can evolve into life-threatening cardiac arrhythmias. The best in vitro test to predict the likelihood of a compound causing QT prolongation, the hERG binding assay, was the test system chosen to study the potential of HY2901 to produce this effect. The human hERG channel, transfected to a stable cell line, was studied electrophysiologically and the percent inhibition of the channel current was reported. In a screening assay mode, HY2901 produced a 10% inhibition of the channel current at a test concentration of 10 nM. To put this in perspective, Seldane used as a positive control produces 100% block of the channel at 60 nM. In a subsequent study with HY2901, the IC50 of HY2901 at the hERG channel was determined to be 93 mM. Peak plasma levels of less than 1.5 mM were seen in rats at the most efficacious dose of 3 mg/kg in the sleep assay. The results of this study indicate that the likelihood of HY2901 causing QT prolongation is very low.

To determine if HY2901 could produce any changes in QT interval, the compound was studied in telemetered Beagle dogs. Dogs were implanted with devices to continuously monitor ECG and arterial blood pressure. Dogs (groups of 4) were studied in a Latin square cross-over design, with each dog receiving 3 different doses and a placebo. Two studies were conducted with doses of 0.3, 1, 3, 10, and 30 mg/kg. HY2901 produced no changes in QT or corrected QT interval at any dose. However, a dose-related sinus tachycardia was observed that persisted at the higher doses for 10–12 hours. The tachycardia persisted for 6–8 hours postdose at 0.3 and 1 mg/kg. A ceiling effect to the heart rate increase seemed to exist with heart rates peaking at approximately 150–160 in both the 10 and 30 mg/kg dose groups. This effect was observed with the compound when dosed intravenously or orally. In addition, a slight increase in blood pressure paralleled the observed tachycardia.

iii. Acute Rat Study

The purpose of this study was to evaluate the toxicity and maximum tolerated dose (MTD) of the test articles when given via oral gavage to rats. Male Crl: CD®(SD)IGS BR rats (3/group) were assigned to 5 groups. At initiation of dosing, animals were approximately 7 weeks old with body weights ranging from 172 to 206 g. Each group received either 50, 100, 150, 200, or 250 mg/kg of HY2901 once daily for 5 days. All surviving animals were sacrificed on Day 6. Assessment of toxicity was based on mortality, clinical observations, and body weight data. Findings were as follows:

One 200 mg/kg rat (B64498) died on Day 1. The remaining rats survived to scheduled sacrifice. Clinical signs for the unscheduled death included sternal recumbency at 1 hour postdose, labored respiration, pale extremities, and coldness to touch at 2 hours postdose, and death at 4 hours postdose in the 200 mg/kg rat (B64498). These signs are consistent with expected toxic effects of the test article.

Hypoactivity was observed in all rats, with the majority exhibiting apparent sleep. In the ≦100 mg/kg rats, these occurred between 30 minutes and 6 hours postdose. The timeframe of both findings occasionally extended in the 150 mg/kg rats, beginning 15 minutes postdose and/or lasting to 8 hours postdose.

A dose-response relationship was observed in the incidence and duration of ataxia. Ataxia occurred in one 50 mg/kg rat at two timepoints (15 minutes apart) on Day 1 and at one timepoint on another day, in two 100 mg/kg rats at isolated timepoints (between 45 minutes and 6 hours postdose), and in all ≧150 mg/kg rats, in which the duration of the ataxia increased for some rats as well.

Day 6 body weights of two 250 mg/kg rats slightly decreased relative to other rats given HY2901.

iv. Acute Dog Study

The purpose of this study was to evaluate the toxicity and the maximum-tolerated dose (MTD) of HY2901 when given as escalating doses via oral gavage to dogs. Two male purebred Beagles were assigned to the study. At initiation of dosing, animals were at least 6 months old with body weights ranging from 8.0 to 10.9 kg. Dogs received dose preparations containing HY2901 once daily for 3 days in escalating doses of 25, 50, or 75 mg/kg, no dose on Day 4, and one dose of 40 mg/kg on Day 5. Dogs were not dosed on Day 4 due to the incidence and severity of clinical signs of toxicity observed at 75 mg/kg.

The dogs were observed at 0.25, 0.5, 0.75, 1.0, 1.5, and 2.0 hours±5 minutes and 4, 6, 8, and 24 hours±15 minutes postdose. They were weighed on Days 1 and 6.

Electrocardiograms were performed and blood pressures were taken prior to dosing and at 1, 4, and 24 hours after the 40 mg/kg dose on Day 5.

Based on the severity of the clinical signs observed the dogs were not dosed on Day 4 and dogs were given a final dose of 40 mg/kg on Day 5. This dose resulted in body tremors, mild to moderate ataxia, excessive salivation and hypoactivity. The test article had minimal effect on body weight. Heart rates of dogs were unaffected by treatment at 40 mg/kg. No significant changes were observed in blood pressure.

The severity and incidence of clinical observations increased with increasing dose.

The clinical signs considered most representative of the toxicity observed included the following:

-   -   1. At 25 mg/kg: No clinical signs of toxicity.     -   2. At 50 mg/kg: Body tremors, mild to severe ataxia, and         hypoactivity.     -   3. At 75 mg/kg: Tremors (entire body, hind limbs, and/or head),         mild to moderate ataxia, hypoactivity.

Based on the range and severity of the clinical signs observed, the MTD is 75 mg/kg for HY2901.

v. 14-Day Rat Study with Recovery Study

The purpose of this study was to evaluate the toxicity of HY2901 when administered via oral gavage to rats for at least 14 days and to assess the reversibility, persistence, or delayed occurrence of any effects after a recovery period of up to 14 days.

Male and female Crl:CD®(SD)IGS BR rats were assigned to seven groups, four main study groups and three groups for toxicokinetics. Each group received dose preparations containing 0.25% methylcellulose, 400 cps in 200 mM acetate buffer, or 10, 30, or 150 mg of test article/kg of body weight (mg/kg/day) at a dose volume of 5 mL/kg.

Assessment of toxicity was based on mortality, clinical and ophthalmic observations, body weights, food consumption, clinical pathology, organ weights, and macroscopic and microscopic findings. Blood samples were collected for toxicokinetic evaluation.

Unscheduled deaths were largely restricted to the 150 mg/kg/day groups, and were higher in females than males. Within the toxicity groups, there were five unscheduled deaths, four of which were in the 150 mg/kg/day group. Of these, two males died on Day 7. Male B66391, was sacrificed moribund with clinical signs of hypoactivity, audible, labored respiration, swollen abdomen and coldness to touch. At necropsy, the gastrointestinal tract of this rat was severely distended with gas. Similar distension was found in Male B66403, which was found dead after being observed with a swollen abdomen, hypoactivity, and audible respiration. Some gas was also found in the cecal lumen of 150 mg/kg/day female B66494, which was sacrificed moribund on Day 7 after it was found in lateral recumbency with tremors and labored respiration. Another 150 mg/kg/day female B66503, was found dead on Day 12 of study after exhibiting convulsions, ataxia, clear oral and nasal discharge, and audible, labored respiration, with unremarkable necropsy findings. All of these 150 mg/kg/day rats were found on microscopic examination to have suppurative inflammation involving the nasal passages, and two also had acute inflammation of the larynx and/or trachea, findings that correlate with the clinical and macroscopic observations and are considered test-article related. A control Female B66463, was found dead on Day 24 following nonspecific signs of debility, and necropsy observations were unremarkable. Among the toxicokinetics groups, one 30 mg/kg/day male was found dead on Day 1 shortly after blood collection. All other unscheduled deaths of toxicokinetic rats were of 150 mg/kg/day females, of which six were found dead from Day 3 through Day 14 of study. Causes of these deaths were not determined, but no gavage error was found.

Expected pharmacological effects of the test article, hypoactivity, ataxia, and the appearance of sleep, were commonly observed. Almost all dosed rats appeared to be asleep at the 1 hour postdose observation on some day or days of the study. The day of onset of this clinical sign was somewhat dose-related:

10 mg/kg/day.some males appeared to be asleep on Day 1 but were unaffected thereafter until approximately Day 12 and the females were not affected on Day 1 but appeared to be asleep at 1 hour postdose from approximately Day 7 through the remainder of dosing;

30 mg/kg/day.several males were affected on Day 1 and then at Day 8 or 9, while the female onset began on or about Day 7;

150 mg/kg/day.several rats of both genders appeared to be asleep at 1 hour postdose at various days during Week 1. As a generalization, this postdose observation became more common in each affected rat as the study advanced. Hypoactivity was also dose-related Episodes of audible respiration and, in some isolated instances, labored respiration, were almost entirely confined to 150 mg/kg/day rats and correlated with the nasal passage inflammation found in unscheduled deaths at this dose. Several of the 150 mg/kg/day rats of each sex exhibited at least one episode of audible respiration.

The test article caused a depression in food consumption in 150 mg/kg/day rats in Week 1, which reached statistical significance in males. This led to a depression in mean body weight of the 150 mg/kg/day males, which lasted through the recovery period, despite a compensatory increase in food consumption in Week 2. Similar but less pronounced trends were observed in 150 mg/kg/day females in Week 1 but there were no parallel changes in mean body weight or body weight change in other groups.

No ophthalmic lesions were observed in any of the groups. Findings in the clinical pathology data were unrelated to treatment.

The mean weights of thymus, lung, and heart for 150 mg/kg/day males were significantly low relative to brain weight at terminal sacrifice. These organ weight findings are considered to be test article-related, although there were no corresponding microscopic findings, and the males from the group assigned to recovery sacrifice did not have low weights of those organs. No treatment-related macroscopic observations or microscopic toxic effects were found in either terminal sacrifice rats or recovery sacrifice rats.

Exposure to HY2901 generally increased as the dose level increased from 10 to 150 mg/kg/day. The increases in Cmax and AUC(0-t) were, in general, greater than dose proportional, except for Cmax at the 150 mg/kg/day dose level on Day 14, where the opposite was true. HY2901 was rapidly absorbed and readily eliminated in rats. Females appeared to have either similar or higher Cmax and AUC(0-t) values compared to males, especially after multiple dosing. Minimum accumulation of HY2901 after multiple dosing in rats was observed.

In conclusion, the no-observed-adverse-effect level (NOAEL) for HY2901 administered by oral gavage to rats for 14 days is 30 mg/kg/day.

vi. 14-Day Dog Study with Recovery Phase

The toxicity and the toxicokinetics of HY2901 when administered daily via oral gavage (Phase 1) or capsules (Phase 2) to dogs for at least 14 days was determined. The reversibility, persistence, or delayed occurrence of observable effects following a 7-day (Phase 1) or 14-day (Phase 2) recovery period was also assessed. Doses of 3, 10, 30, and 70 mg/kg/day were studied. All Phase 1 and 2 dogs survived until scheduled sacrifice.

There were no treatment-related clinical observations in the 3 mg/kg/day Phase 1 dogs. In Phase 2, treatment-related head tremors, ataxia, hypoactivity, and excessive salivation were noted at least once in different males; hypoactivity once in one female; and sporadic vomiting (white, foamy or containing food) were noted in females. There were no remarkable clinical observations during the Phase 1 and 2 recovery periods.

There were no changes in respiration rates, rectal body temperatures, body weights, food consumption, electrocardiograms, and ophthalmic examinations attributed to HY2901 in Phase 1 and 2. Sinus tachycardia (heart rate above 190 beats/minute) was noted during Phase 2 in one male on Day 3 (predose and 4 hours postdose), on Day 14 (2 and 4 hours postdose), and on Day 29 (after 14-day recovery). Also three Phase 2 females were noted with sinus tachycardia; one on Day 3 (4 hours postdose) and on Day 14 (2 and 4 hours postdose), one on Day 14 (2 hours postdose), and one on Day 29 (after 14-day recovery). No unequivocal evidence is present to suggest a direct treatment effect as evidenced by inconsistency in tachycardia observations; therefore, these findings were considered incidental to the treatment.

Clinical pathology data were generally unremarkable and similar among the 0 and 3 mg/kg/day groups at the designated intervals during Phase 1, and were unremarkable for the 70 mg/kg/day dogs at all collection intervals of Phase 2. There was no evidence in the clinical laboratory data of an effect from the administration of HY2901.

In conclusion, gavage administration of HY2901 at 3 mg/kg/day and at 70 mg/kg/day via gelatin capsule to purebred Beagles for at least 14 days resulted in a NOAEL for HY2901 treatment of 70 mg/kg/day.

The above methods and protocols are useful in the pre-clinical evaluation of other modified anti-histamine of the invention.

EXAMPLE 8 Binding Specificity of Compound 37 for H1 Histamine Receptors and M1, M2, and M3 Cholinergic Receptors

Binding assays were performed using compound 37 (HYP10073) in competitive binding assays with known standards for the H1 histamine receptor, and the M1, M2, and M3 muscarinic receptors.

First, the binding specificity of compound 37 for a variety of receptors was evaluated. The percentage inhibition (average; N=2) for these receptors is shown below in Table 12.

TABLE 12 Inhibitory Effect of Compound 37 Receptor 1.0E−6 NEUROTRANSMITTER RELATED Adenosine, Non-selective 6.49% Adrenergic, Alpha 1, Non-selective 6.56% Adrenergic, Alpha 2, Non-selective −3.79%   Adrenergic, Beta, Non-selective 6.97% Dopamine Transporter 2.14% Dopamine, Non-selective 21.10%  GABA A, Agonist Site 20.18%  GABA A, BDZ, alpha 1 site −7.13%   GABA-B 2.17% Glutamate, AMPA Site 3.59% Glutamate, Kainate Site 1.51% Glutamate, NMDA Agonist Site −5.56%   Glutamate, NMDA, Glycine (Stry-insens Site)  −12.50%    Glycine, Strychnine-sensitive 1.15% Histamine, H1 93.13%  Histamine, H2 0.80% Histamine, H3 5.11% Melatonin, Non-selective 11.29%  Muscarinic, M1 (hr) 5.11% Muscarinic, M2 (hr) 14.62%  Muscarinic, Non-selective, Central 12.84%  Muscarinic, Non-selective, Peripheral 5.37% Nicotinic (a-Bungarotoxin Insensitive) 1.69% Norepinephrine Transporter 19.51%  Opioid, Non-selective −9.30%   Orphenin (hr) 3.53% Serotonin Transporter 11.46%  Serotonin, Non-selective 21.45%  Sigma, Non-selective 13.27%  STEROIDS Estrogen −4.68%   Testosterone (cytosolic) 0.24% ION CHANNELS Calcium Channel, Type L (Dihydropyridine Site) 5.82% Calcium Channel, Type N 3.45% Potassium Channel, ATP-Sensitive 26.16%  Potassium Channel, Ca2+ Act., VI  −12.71%    Potassium Channel, I[Kr] (hERG) (hr) −5.23%   Sodium, Site 2 −4.12%   SECOND MESSENGERS Nitric Oxide, NOS (Neuronal-Binding) 17.21%  PROSTAGLANDINS Leukotriene, LTD4  −20.09%    Thromboxane A2 (h) 6.55% GROWTH FACTORS/HORMONES Corticotropin Releasing Factor, Non-selective 4.31% Oxytocin −5.82%   Platelet Activating Factor, PAF −1.15%   Thyrotropin Releasing Hormone, TRH −2.98%   BRAIN/GUT PEPTIDES Angiotensin II, AT1 (h) 12.03%  Angiotensin II, AT2 1.51% Bradykinin, BK2 −3.04%   Cholecystokinin, CCK1 (CCKA) 8.92% Cholecystokinin, CCK2 (CCKB) 3.98% Endothelin, ET-A (h) 10.15%  Endothelin, ET-B (h) −6.51%   Galanin, Non-Selective −5.07%   Neurokinin, NK1 10.27%  Neurokinin, NK2 (NKA) (hr) −4.17%   Neurokinin, NK3 (NKB) −0.23%   Vasoactive Intestinal Peptide, Non-selective 2.51% Vasopressin 1 11.55%  ENZYMES Choline Acetyltransferase 6.51% Esterase, Acetylcholine 2.54% Glutamic Acid Decarboxylase −4.76%   Oxidase, MAO-A, Peripheral  −17.23%    Oxidase, MAO-B, Peripheral 4.24%

Values in Table 12 are expressed as percentage inhibition of specific binding, and these values represent the average of replicate tubes at each of the concentrations tested. Bolded values represent inhibition of 50% or greater.

The binding specificity for compound 37 for histamine H1 receptor and muscarinic M1, M2 and M3 receptors was further evaluated using the binding assays described above.

In particular, the in vitro H1 binding assay measured the specific binding of compound 37 to the H1 receptor and compared the measured specific binding with the specific binding of known standard (i.e., reference compound), triprolidine. (See e.g., Chang et al., J. Neurochem., 32:1653–63 (1979) (with modifications); Martinez-Mir, et al., Brain Res., 526:322–27 (1990); and Haaksme, et al., Pharmac. Ther., 47:73–104 (1990)).

In these tests, the H1 receptor was a bovine cellular membrane, and a radioligand, [³H]Pyrilamine (15–25 Ci/mmol) at a final ligand concentration of 2.0 nM was used to detect specific binding of compound 37 for the H1 receptor. The assay characteristics include a K_(D) (binding affinity) of 1.3 nM and a B_(max) (receptor number) of 6.2 fmol/mg tissue (wet weight). Tripolidine (10 μM) was used as the non-specific determinant, reference compound and positive control. Binding reactions were carried out in 50 mM NA-KPO₄ (pH 7.5) at 25° C. for 60 minutes. The reaction was terminated by rapid vacuum filtration onto glass fiber filters. The level of radioactivity trapped on the filters was measured and compared to control values to ascertain any interaction between compound 37 and the H1 binding site.

The binding curves for compound 37 and triprolidine binding to the H1 receptor are shown in FIG. 2. The calculated IC50 and K_(i) values for triprolidine and compound 37 are shown below in Table 13.

TABLE 13 IC50/K_(i) Determination for Compound 37 IC50 K_(i) Slope Triprolidine 6.92E−9 2.65E−9 −0.76 Compound 37 6.75E−8 2.58E−8 −0.99

The H1 specific binding and % inhibition for compound 37 at various concentrations, as determined using the in vitro H1 binding assay, are shown below in Table 14.

TABLE 14 H1 Binding of Compound 37 at Varying Concentrations (Average: N = 2) Receptor Concentration % Inhibition % Specific Binding NEUROTRANSMITTER RELATED Histamine, H1 1.0E−9 2.99% 97.01% 1.0E−8 3.60% 91.40% 3.0E−8 30.37% 69.63% 1.0E−7 60.82% 39.13% 3.0E−7 81.03% 18.97% 1.0E−6 93.75% 6.25% 3.0E−6 93.26% 6.74% 1.0E−5 96.79% 3.21%

The values in Table 13 represent the average of replicate tubes at each of the concentrations tested.

The in vitro M1 binding assay measured the specific binding of compound 37 to M1 and compared this measured binding specificity with the specific binding of the reference compound (−)-scopolamine, MeBr. (See e.g., Buckley, et al., Mol. Pharmacol. 35:469–76 (1989) (with modifications)).

In this assay, the M1 muscarinic receptor was a human recombinant M1 expressed in CHO cells, and a radioligand, [³H]-scopolamine, N-methyl chloride (80–100 Ci/mmol) at a final ligand concentration of 0.5 nM was used to detect specific binding for M1. (−)-scopolamine, methyl bromide (methylscopolamine bromide) was used as the non-specific determinant, reference compound and positive control. The assay characteristics include a K_(D) (binding affinity) of 0.05 nM and a B_(max) (receptor number) of 4.2 pmol/mg protein (1.0 μM). Binding reactions were carried out in PBS for 60 minutes at 25° C. The reaction was terminated by rapid vacuum filtration onto glass fiber filters. The level of radioactivity trapped on the filters was measured and compared to control values to ascertain any interaction between a given test compound and the cloned muscarinic M1 binding site.

The binding curves for compound 37 and (−)-scopolamine, MeBr binding to the M1 receptor are shown in FIG. 3. The calculated IC50 and K_(i) values for (−)-scopolamine, MeBr and compound 37 are shown below in Table 15.

TABLE 15 IC50/K_(i) Determination for Compound 37 IC50 K_(i) Slope (−)-scopolamine, MeBr 6.08E−10 6.47E−11 −1.14 Compound 37 N/A N/A N/A N/A refers to a value >10,000

The M1 specific binding and % inhibition for compound 37 at various concentrations, as determined using the in vitro M1 binding assay, are shown below in Table 16.

TABLE 16 M1 Binding of Compound 37 at Varying Concentrations (Average: N = 2) Receptor Concentration % Inhibition % Specific Binding NEUROTRANSMITTER RELATED Muscarinic, M1 (hr) 1.0E−9 −10.93% 110.93% 1.0E−8 −16.93% 116.93% 3.0E−8 −6.82% 106.82% 1.0E−7 1.61% 98.39% 3.0E−7 2.87% 97.13% 1.0E−6 −5.22% 105.22% 3.0E−6 −11.53% 111.53% 1.0E−5 −7.57% 107.57%

The values in Table 13 represent the average of replicate tubes at each of the concentrations tested.

The M2 binding assay measured the specific binding of the M2 receptor and compared the measured specific binding with the specific binding of a given test compound to M2 and comparing it with the specific binding of a reference compound, (−)-scopolamine, MeBr. (See e.g, Buckley, et al., Mol. Pharmacol. 35:469–76 (1989) (with modifications)).

In this assay, the M2 muscarinic receptor was a human recombinant M2 expressed in CHO cells, and a radioligand, [³H]-scopolamine, N-methyl chloride (80–100 Ci/mmol) at a final ligand concentration of 0.5 nM was used to detect specific binding for M1. The assay characteristics included a K_(D) (binding affinity) of 0.29 nM and a B_(max) (receptor number) of 2.1 pmol/mg protein. (−)-scopolamine, methyl-, bromide (methylscopolamine bromide) (1.0 μM) was used as the non-specific determinant, reference compound and positive control. Binding reactions were carried out in PBS for 60 minutes at 25° C. The reaction was terminated by rapid vacuum filtration onto glass fiber filters. The level of radioactivity trapped on the filters was measured and compared to control values to ascertain any interaction between a given test compound and the cloned muscarinic M2 binding site.

The binding curves for compound 37 and (−)-scopolamine, MeBr for the M2 receptor are shown in FIG. 4. The calculated IC50 and K_(i) values for (−)-scopolamine, MeBr and compound 37 are shown below in Table 17.

TABLE 17 IC50/K_(i) Determination for Compound 37 IC50 K_(i) Slope (−)-scopolamine, MeBr 6.47E−10 2.64E−11 −0.89 Compound 37 N/A N/A N/A N/A refers to a value >10,000

The M2 specific binding and % inhibition for compound 37 at various concentrations, as determined using the in vitro M2 binding assay, are shown below in Table 18.

TABLE 18 M2 Binding of Compound 37 at Varying Concentrations (Average: N = 2) Receptor Concentration % Inhibition % Specific Binding NEUROTRANSMITTER RELATED Muscarinic, M2 (hr) 1.0E−9 −2.57% 102.57% 1.0E−8 −14.04% 114.04% 3.0E−8 −12.52% 112.62% 1.0E−7 −17.74% 117.74% 3.0E−7 −9.94% 109.94% 1.0E−6 −2.53% 102.53% 3.0E−6 −5.10% 105.10% 1.0E−5 5.61% 94.39%

The values in Table 13 represent the average of replicate tubes at each of the concentrations tested.

The M3 binding assay measured the specific binding of compound 37 to the M3 receptor and compared the measured specific binding with the specific binding of a reference compound, (−)-scopolamine, MeBr. (See e.g., Buckley, et al., Mol. Pharmacol. 35:469–76 (1989) (with modifications)).

In this assay, the M3 muscarinic receptor was a human recombinant M3 expressed in CHO cells, and a radioligand, [³H]-scopolamine, N-methyl chloride (80–100 Ci/mmol) at a final ligand concentration of 0.2 nM was used to detect specific binding for M1. The assay characteristics included a K_(D) (binding affinity) of 0.14 nM and a B_(max) (receptor number) of 4.0 pmol/mg protein. (−)-scopolamine, methyl-, bromide (methylscopolamine bromide) (1.0 μM) was used as the non-specific determinant, reference compound and positive control. Binding reactions were carried out in 50 mM TRIS-HCl (pH 7.4) containing 10 mM MgCl₂, 1 mM EDTA for 60 minutes at 25° C. The reaction was terminated by rapid vacuum filtration onto glass fiber filters. The level of radioactivity trapped on the filters was measured and compared to control values to ascertain any interaction between a given test compound and the cloned muscarinic M3 binding site.

The binding curves for compound 37 and (−)-scopolamine, MeBr for the M3 receptor are shown in FIG. 5. The calculated IC50 and K_(i) values for (−)-scopolamine, MeBr and compound 37 are shown below in Table 19.

TABLE 19 IC50/K_(i) Determination for Compound 37 IC50 K_(i) Slope (−)-scopolamine, MeBr 3.64E−10 1.32E−10 −0.55 Compound 37 N/A N/A N/A N/A refers to a value >10,000

The M3 specific binding and % inhibition for compound 37 at various concentrations, as determined using the in vitro M3 binding assay, are shown below in Table 20.

TABLE 20 M3 Binding of Compound 37 at Varying Concentrations (Average: N = 2) Receptor Concentration % Inhibition % Specific Binding NEUROTRANSMITTER RELATED Muscarinic, M3 (hr) 1.0E−9 −0.65% 100.65% 1.0E−8 −6.34% 108.34% 3.0E−8 6.99% 93.01% 1.0E−7 6.85% 93.15% 3.0E−7 5.55% 94.45% 1.0E−6 0.79% 99.21% 3.0E−6 5.41% 94.59% 1.0E−5 4.27% 95.73%

The values in Table 13 represent the average of replicate tubes at each of the concentrations tested.

EXAMPLE 9 SCORE-2000 Data for Compound 37

The effect of compound 37 (also referred to herein as HY-10073) on sleep and wakefulness in adult male Wistar rats were determined using the “SCORE-2000™” (Hypnion, Worcester, Mass.)—an internet-based sleep-wake and physiological monitoring system described above in Example 2.

Sleep-wakefulness, locomotor activity and body temperature were monitored in male Wistar rats treated with compound 37 at a concentration of either 10 mg/kg PO (i.e., oral administration) or 30 mg/kg PO. Treatments were administered at CT-18, the peak of the activity dominated period (6 hours after lights-off), and produced soporific (sleep-inducing) effects characterized by increased non-REM sleep time, increased sleep continuity, but without evidence of REM sleep inhibition or rebound insomnia.

When compound 37 was administered at 10 mg/kg PO, peak NREM sleep time was 64% per hour. Cumulative NREM sleep time, adjusted for baseline and relative to vehicle, increased by 53 minutes±6 minutes. The absolute longest sleep bout post-treatment was 18.3 minutes, while the longest sleep bout (also referred to herein as “Longest Uninterrupted Sleep Bout” (LUSB)), adjusted for baseline and relative to vehicle, was 10.8 minutes±2.7 minutes. The absolute average sleep bout was 9 minutes, while the average sleep bout length, adjusted for baseline and relative to vehicle, increased by 5.3 minutes±1.4 minutes.

Also, administration of compound 37 at a concentration of 10 mg/kg, did not produce any REM inhibition or rebound insomnia. Furthermore, there was no disproportional reduction in either locomotor activity (LMA) or body temperature.

When compound 37 was administered at 30 mg/kg PO, peak NREM sleep time was 72% per hour. Cumulative NREM sleep time, adjusted for baseline and relative to vehicle, increased by 62 minutes±9 minutes. The absolute longest sleep bout post-treatment was 25 minutes, while the longest sleep bout (also referred to herein as “Longest Uninterrupted Sleep Bout” (LUSB)), adjusted for baseline and relative to vehicle, was 17.1 minutes±3.6 minutes. The absolute average sleep bout was 9 minutes, while the average sleep bout length, adjusted for baseline and relative to vehicle, increased by 5.6 minutes±1.5 minutes.

Also, administration of compound 37 at a concentration of 30 mg/kg, did not produce any appreciable REM inhibition at CT-18. No rebound insomnia was observed with the 30 mg/kg administration. Furthermore, there was no disproportional reduction in LMA. The drop in body temperature occurred only at this high dose of compound 37 (i.e., an unacceptable drop in body temperature was only observed when compound 37 was administered at such high dosages).

The sleep consolidating effects of compound 37 administered at a concentration of 30 mg/kg (PO) at CT-18 is shown in FIG. 6. (CT-18 is indicated as a triangle on the x-axis of FIG. 6). As seen in FIG. 6, a robust increase in the increase in the peak sleep bout duration was observed in the initial 2–3 hours post treatment.

EXAMPLE 10 Evaluation of the Analgesic Activity of HY-2901 (Compound 49a)

The objective of this example was to determine the analgesic activity of HY-2901 (Also referred to herein as Compound 49a) following oral administration. Analgesic activity was assessed abdominal spasm test in the rat and mouse. Analgesic activity is also assessed using the tail clip test in the mouse, tail flick test in the rat, Randall-Selitto test in the rat and comparisons are made with a vehicle control group. Reference compounds ASA (acetylsalicylic acid) and morphine are also included for comparison.

The tail clip and tail flick test provide useful information about the central analgesic activity of the test article. The Randall-Selitto test provides information on the compound's ability to modify a hyperalgesic state and the abdominal spasm test provides information on the peripheral analgesic activity of the test article. The test article is administered by oral gavage, this being the intended clinical route of administration. The dose levels employed are expected to encompass the efficacy dose and provide an adequate safety margin.

Test Article, Reference Compound and Irritant Formulation

All formulations were prepared on each day of dosing. The test article (HY-2901) was formulated in 0.25% (w/v) MC at the highest concentration required. Lower doses were obtained by serial dilution of the highest concentration using 0.25% (w/v) MC. The reference compound, acetylsalicylic acid, was formulated in 0.25% (w/v) MC at the required concentrations. Brewer's yeast was formulated in water for injection at the required concentration. Acetic acid was diluted with water for injection to provide the required concentration for administration.

Dose levels will be expressed in terms of the amount of test article I reference compound,/irritant administered without regard to purity or active content.

Animals

An adequate number of male Crl:CD-I(ICR)BR mice and Wistar rats were obtained from Charles River (UK) Ltd., Margate, Kent. The mice were approximately 4 weeks of age and weigh between 18 and 22 g on arrival. The rats were approximately 5 weeks of age and weigh between 150 and 170 g on arrival. The age and weight of the animals at the start of the study was documented in the raw data and final report,

The animals were housed in groups appropriate to the size of caging used, in cages that conform to the Code of Practice for the housing and care of animals used in the Scientific Procedures Act (Home Office Animals Scientific Procedures Act 1986). Bedding was provided on a weekly basis to each cage by use of clean Aspen wood chips (Dates and Ltd, Manchester, UK). The bedding was analyzed for specific contaminants and the results retained on file at Covance. The cages were cleaned and dried before use. Aspen chew blocks were placed within the cages as a form of environmental enrichment. Routinely, holding rooms were maintained within acceptable limits for temperature and relative humidity (nominally 19 to 25° C. and 40 to 70%, respectively). These rooms are illuminated by fluorescent light for 1,2 hours out of each 24 hour cycle and designed to receive at least 15 fresh air changes per hour.

RM1.(E).SQC., (Special Diets Services Ltd., Witham, UK) and water from the mains tap supply will be provided ad libitum, except where specified below. These are routinely analyzed for specific constituents and are not known to contain any biological or chemical entity which might interfere with the test system. The treatment groups employed for the study were as shown in Table 21:

TABLE 21 Treatment Groups. Group Treatment Dose level (mg/kg) conc. (mg/mL) #of animals 1 Vehicle — — 8 2 HY-2901 3 0.3 8 3 HY-2901 10 1.0 8 4 HY-2901 30 3.0 8 5 Morphine 100 10.0 8

Measurements of pressure were taken from the left and right hind paws of each animal immediately prior to administration of vehicle, test article or reference compound and at 30, 60, 1,20 and 240 minutes post-oral administration. The order of the pressure measurements was left paw followed by right paw.

Abdominal Spasm Test in the Rat

Each animal received a single administration of vehicle, test article or reference compound by oral gavage, using a constant dose volume 10 mg/kg. Individual dose volumes were based on individual body weights obtained on the day of dosing. The treatment groups are shown in Table 22.

TABLE 22 Treatment Groups. Group Treatment Dose level (mg/kg) Conc, (mg/mL) # of animals 1 Vehicle — — 6 2 HY-2901 3 0.3 6 3 HY-2901 10 1.0 6 4 HY-2901 30 3.0 6 5 ASA 100 10.0 6

Forty-five minutes following oral administration each animal received a 1 mL intraperitoneal injection of 1% acetic acid. Animals were immediately placed into individual observation chambers and the number of abdominal spasms elicited over the subsequent 25-minute period was recorded.

Abdominal Spasm Test in the Mouse

Each animal received a single administration of vehicle, test article or reference compound by oral gavage, using a constant dose volume 10 mL/kg. Individual dose volumes were based on individual body weights obtained on the day of dosing. The treatment groups are shown in Table 23.

TABLE 23 Treatment Groups. Group Treatment Dose level (mg/kg) Conc. (mg/mL) # of animals 1 Vehicle — — 6 2 HY-2901 3 0.3 6 3 HY-2901 10 1.0 6 4 HY-2901 30 3.0 6 5 ASA 100 10.0 6

Forty-five minutes following oral administration each animal received a 0.25 mL intraperitoneal injection of 0.5% acetic acid. Animals were immediately placed into individual observation chambers and the number of abdominal spasms elicited over the subsequent 25-minute period was recorded.

Terminal Procedures

At the end of each test, the animals were humanely killed by a Schedule 1 method (e.g. exposure to carbon dioxide gas in a rising concentration followed by dislocation of the neck) and discarded without necropsy. If an animal showed any sign of serious discomfort during the study it was sacrificed immediately and humanely. Any animal found dead or killed prematurely during the study was subjected to a necropsy. A macroscopic examination was performed, after opening the thoracic and abdominal cavities, by observing the appearance of the tissues in situ. Any abnormalities were recorded.

Results

TABLE 24 Effects of HY-2901 on group mean acetic acid-induced abdominal spasms in the rat following oral administration Group mean (=sd) number pf Oral Dose level abdominal spasms recorded Group Treatment (mg/kg) in a 25-minute period 1 Vehicle — 33 ± 17.2 (0.25% MC) 2 HY-2901 3 31 ± 9.0  3 HY-2901 10 25 ± 16.4 4 HY-2901 30 17 ± 13.8 5 ASA 100 1 ± 2.3

TABLE 25 Effects of HY-2901 on acetic acid-induced abdominal spasms in the rat following oral administration - individual animal data Number of abdominal Oral Dose level Animal spasms recorded in Group Treatment (mg/kg) I.D. a 25-minute period 1 Vehicle — 1 8 (0.25% MC) 2 41 3 20 4 50 5 51 6 30 2 HY-2901 3 7 42 8 17 9 26 10 29 11 31 12 39 3 HY-2901 10 13 57 14 23 15 20 16 24 17 19 18 9 4 HY-2901 30 19 37 20 20 21 23 22 1 23 1 24 18 5 ASA 100 25 0 26 1 27 6 28 1 29 0 30 0

TABLE 26 Effects of HY-2901 on group mean acetic acid-induced abdominal spasms in the mouse following oral administration Group mean (±sd) number of Oral Dose level abdominal spasms recorded Group Treatment (mg/kg) in a 25 minute period 1 Vehicle — 37 ± 26.8 (0.25% MC) 2 HY-2901 3 6 ± 6.2 3 HY-2901 10 1 ± 2.0 4 HY-2901 30 0 ± 0.0 5 ASA 100 29 ± 29.9

TABLE 27 Effects of HY-2901 on acetic acid-induced abdominal spasms in the mouse following oral administration - individual animal data Number of abdominal Oral Dose level Animal spasms recorded in Group Treatment (mg/kg) I.D. a 25-minute period 1 Vehicle — 1 2 (0.25% MC) 2 47 3 18 4 59 5 72 6 23 2 HY-2901 3 7 0 8 1 9 0 10 10 11 7 12 15 3 HY-2901 10 13 0 14 0 15 0 16 2 17 0 18 5 4 HY-2901 30 19 0 20 0 21 0 22 0 23 0 24 0 5 ASA 100 25 17 26 8 27 45 28 82 29 1 30 23

EXAMPLE 11 Comparison of the Activity of HY-2901 (Compound 49a), HY-10519 (Compound 47b) and Analogs

To determine the effect of linker composition on sleep-promoting activity, the following compounds were assayed (as described above):

The comparative data is shown in Table 28, unless otherwise noted, binding was measured with the bovine receptors, H1(hR) is the human H1 receptor, 5HT2a (h) is the human 5HT2a receptor. Binding numbers are presented in nM values. Primate T½ and C max are measured at 1 mg/kg.

TABLE 28 H1 nM 5HT2a 5HT2a HY# (hR) H1 M1 M2 M3 α1 α2 D1 D2 (rat) (h) HERG 10027 111 >10,000 >10,000 >10,000 94.8 677 1.00% 10518 35 52.3 >10,000 >10,000 >10,000 2850 >10,000 >10,000 >10,000 197 422 3.90% 10519 34 19.8 >10,000 >10,000 >10,000 >10,000 >10,000 >10,000 56 541 6.10% 10520 43 22.5 >10,000 >10,000 >10,000 1090 >10,000 >10,000 >10,000 55.8 396 56.00% NREM Rat Primate LUSB 1 LUSB 3 LUSB 10 LUSB 30 cumul. HY# T_(1/2) C_(max) T_(1/2) C_(max) mg/kg mg/kg mg/kg mg/kg 10 mpk 10027 0.694 127 3.43 699 2.9 ± 1.5 5.5 ± 2.2 17.0 ± 2.5 9.1 ± 3.1 47 ± 7 10518 6.7 ± 2.3  7.9 ± 1.7 46 ± 7 10519 0.870 174 1.25 182 5.6 ± 1.9 12.0 ± 3.4 6.9 ± 2.3 45 ± 8 10520 4.9 ± 1.7 10.0 ± 2.2 41 ± 8

OTHER EMBODIMENTS

While the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. 

1. A compound having the formula of Compound 47b:

or a salt thereof.
 2. The compound of claim 1, wherein Compound 47b is a pharmaceutically acceptable salt.
 3. The compound of claim 2, wherein the salt is an acid addition salt.
 4. The compound of claim 2, wherein the salt is a hydrochloride salt.
 5. The compound of claim 4, wherein the compound is:


6. A composition comprising Compound 47b:

or a salt thereof, and at least one pharmaceutically acceptable excipient.
 7. The composition of claim 6, wherein the compound is a pharmaceutically acceptable salt.
 8. The composition of claim 6, wherein the salt is an acid addition salt.
 9. The composition of claim 8, wherein the salt is a hydrochloride salt.
 10. The composition of claim 9, wherein the composition is:


11. A method of modulating sleep in a subject, comprising administering to a subject in need thereof a therapeutically effective amount of Compound 47b:

or a pharmaceutically acceptable salt thereof.
 12. The method of claim 11, wherein the sleep modulation is selected from decreasing the time to sleep onset, increasing the average sleep bout length, and increasing the maximum sleep bout length.
 13. The method of claim 11, wherein the sleep modulation treats the sleep disorder selected from the group consisting of from circadian rhythm abnormality, insomnia, parasomnia, sleep apnea syndrome, narcolepsy and hypersomnia.
 14. The method of claim 13, wherein the sleep disorder is circadian rhythm abnormality.
 15. The method of claim 13, wherein the sleep disorder is insomnia.
 16. The method of claim 13, wherein the sleep disorder is sleep apnea.
 17. The method of claim 13, wherein the sleep disorder is narcolepsy.
 18. The method of claim 13, wherein the sleep disorder is hypersomnia.
 19. The method of claim 11, wherein the compound or pharmaceutically acceptable salt, is administered as a pharmaceutical composition comprising at least one pharmaceutically acceptable excipient.
 20. The method of claim 11, wherein the compound or pharmaceutically acceptable salt is co-administered with one or more additional therapies.
 21. The method of claim 20, wherein the additional therapy is a drug.
 22. The method of claim 20, wherein the additional therapy is continuous positive airway pressure treatment.
 23. The method of claim 20, wherein the additional therapy is light therapy.
 24. The method of claim 20, wherein the additional therapy is electrical stimulation.
 25. The method of claim 20, wherein the additional therapy is cognitive therapy.
 26. The method of claim 20, wherein the additional therapy is circadian rhythm modification.
 27. The method of claim 20, wherein the additional therapy is surgery.
 28. The method of claim 11, wherein the subject is a human. 